ALBERT

Beschreibung:    In this work, Monte Carlo simulation was used to model the dynamic hysteresis behavior of magnetic/non-magnetic multilayers in the framework of Heisenberg model using the spin-flip algorithm. The purpose is to investigate the hysteresis properties while varying the direction of external applied magnetic field and temperature taking account interface composition of magnetic/non-magnetic atoms. From the results, with thermal variation and interface composition, the simulated hysteresis loops change significantly due to the competition between magnetic anisotropy in magnetic films and the presence of isolated clusters at the interface. Content Type Journal Article Category Original Paper Pages 1-4 DOI 10.1007/s10948-012-1492-6 Authors A. Razouk, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, B.P. 523, 23000 Béni Mellal, Morocco M. Sahlaoui, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, B.P. 523, 23000 Béni Mellal, Morocco M. Sajieddine, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, B.P. 523, 23000 Béni Mellal, Morocco Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The photoluminescence properties of alkali-earth magnesium silicates (M 2 MgSi 2 O 7 , M=Ca, Sr, and Ba) doped with Eu 2+ were investigated. Solid solutions of Ba x Sr 2− x Si 2 O 7 , Ca 2 MgSi 2 O 7 , and Sr 2 MgSi 2 O 7 were prepared. Ba x Sr 2− x Si 2 O 7 retained a tetragonal crystal structure similar to the structure of the other compounds up to a stoichiometry of x =1.6, which enabled a systematic study of the common structure. Monoclinic Ba 2 MgSi 2 O 7 was prepared, and the luminescence properties were compared with those of other samples. The emission and excitation spectra of tetragonal M 2 MgSi 2 O 7 (M=Ca, Sr, and Ba) changed as a function of the covalency, site symmetry, and crystal field strength. The luminescence properties showed excellent agreement with theoretical predictions based on these factors. The Stokes shift differentiated the emission behaviors of the tetragonal and monoclinic structures. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-4914-z Authors T. Kim, Department of Materials Science and Engineering, Seoul National University, Seoul, 151-742 Republic of Korea Y. Kim, Department of Materials Science and Engineering, Seoul National University, Seoul, 151-742 Republic of Korea S. Kang, Department of Materials Science and Engineering, Seoul National University, Seoul, 151-742 Republic of Korea Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We present a novel approach to extend optical coherence tomography (OCT) to the extreme ultraviolet (XUV) and soft X-ray (SXR) spectral range. With a simple setup based on Fourier-domain OCT and adapted for the application of XUV and SXR broadband radiation, cross-sectional images of semiconductors and organic samples becomes feasible with current synchrotron or laser-plasma sources. For this purpose, broadband XUV radiation is focused onto the sample surface, and the reflected spectrum is recorded by an XUV spectrometer. The proposed method has the particular advantage that the axial spatial resolution only depends on the spectral bandwidth. As a consequence, the theoretical resolution limit of XUV coherence tomography (XCT) is in the order of nanometers, e.g., 3 nm for wavelengths in the water window (280–530 eV). We proved the concept of XCT by calculating the reflectivity of one-dimensional silicon and boron carbide samples containing buried layers and found the expected properties with respect to resolution and penetration depth confirmed. Content Type Journal Article Category Rapid Communication Pages 1-7 DOI 10.1007/s00340-012-4934-8 Authors S. Fuchs, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany A. Blinne, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany C. Rödel, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany U. Zastrau, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany V. Hilbert, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany M. Wünsche, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany J. Bierbach, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany E. Frumker, Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada E. Förster, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany G. G. Paulus, Institute of Optics and Quantum Electronics, Friedrich-Schiller University of Jena, Max-Wien-Platz 1, 07743 Jena, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Next-generation laser diode arrays with integrated ‘on-chip’ volume holographic gratings can provide high power with spectrally narrowed output that can be tuned about the rubidium D 1 line—without causing significant changes to the laser’s flux or spectral profile. These properties were exploited to independently evaluate the effects of varying the laser centroid wavelength and power on batch-mode Rb/ 129 Xe spin-exchange optical pumping (SEOP) as functions of xenon partial pressure and cell temperature. Locally optimized SEOP was often achieved with the laser tuned to either the red or blue side of the Rb D 1 line; global optimization of SEOP was observed at lower cell temperatures and followed the D 1 absorption profile, which was asymmetrically broadened and red-shifted from the nominal wavelength. The complex dependence of the optimal wavelength for laser excitation on the cell temperature and Xe density appears to result from an interplay between cell illumination and the Rb/ 129 Xe spin-exchange rate, as well as [Xe] cell -dependent changes to the Rb absorption lineshape that are in qualitative agreement with expectations based on previous work [Romalis et al., Phys. Rev. A, 56:4569–4578, ( 1997 )], but significantly greater in magnitude. These next-generation lasers provide a ∼2–3-fold improvement in 129 Xe polarization compared to conventional broadband lasers. Content Type Journal Article Category Invited Paper Pages 1-14 DOI 10.1007/s00340-012-4924-x Authors N. Whiting, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA P. Nikolaou, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA N. A. Eschmann, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA M. J. Barlow, Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, NG7 2RD UK R. Lammert, QPC Lasers Division, Laser Operations LLC, Sylmar, CA 91342, USA J. Ungar, QPC Lasers Division, Laser Operations LLC, Sylmar, CA 91342, USA W. Hu, QPC Lasers Division, Laser Operations LLC, Sylmar, CA 91342, USA L. Vaissie, QPC Lasers Division, Laser Operations LLC, Sylmar, CA 91342, USA B. M. Goodson, Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We theoretically and experimentally investigate the Fraunhofer diffraction pattern of a vortex beam passing through an annular ellipse aperture. It is found that the pattern of the far-field diffraction intensity distribution exhibits some dark spots, which become clearer with increasing the value of the ellipticity factor of the annular ellipse aperture. The diffraction phenomenon is more obvious with increasing the value of the ratio of the inner long axis (or short axis) to the outer side of the annular ellipse aperture. The number of the dark spots in the Fraunhofer diffraction intensity distribution is just equal to the topological charge value of the measured optical vortex, and the centre of each dark spot is just a phase-singularity point. Based on this property, we can measure the topological charge of an optical vortex beam. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-4911-2 Authors H. Tao, College of Information Science and Engineering, Institute of Optics and Photonics, Huaqiao University, Xiamen, Fujian 361021, China Y. Liu, College of Information Science and Engineering, Institute of Optics and Photonics, Huaqiao University, Xiamen, Fujian 361021, China Z. Chen, College of Information Science and Engineering, Institute of Optics and Photonics, Huaqiao University, Xiamen, Fujian 361021, China J. Pu, College of Information Science and Engineering, Institute of Optics and Photonics, Huaqiao University, Xiamen, Fujian 361021, China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Eu 3+ and Sm 3+ co-doped molybdate phosphors have been synthesized via hydrothermal method. The phosphors have the advantages of narrower particle size distribution and regular homogeneous shape. The luminescent properties of the molybdate phosphors were systematically studied. The introduction of Sm 3+ into the red-emitting phosphors can generate a strong excitation line at 405 nm, originating from the 6 H 5/2 → 4 K 11/2 transition of Sm 3+ , significantly extending the excitation region for matching the near-ultraviolet light-emitting diodes (−400 nm). Energy transfer from Sm 3+ to Eu 3+ was observed. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-4916-x Authors X.-j. Geng, School of Materials and Metallurgy, Northeastern University, Shenyang, 110004 P.R. China Y.-w. Tian, School of Materials and Metallurgy, Northeastern University, Shenyang, 110004 P.R. China Y.-j. Chen, College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, 110142 P.R. China L.-j. Xiao, College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, 110142 P.R. China Y. Xie, College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, 110142 P.R. China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We study pump requirements to produce femtosecond X-ray laser pulses at saturation from inner-shell transitions in the amplified spontaneous emission regime. Since laser-based betatron radiation is considered as the pumping source, we first study the impact of the driving laser power on its intensity. Then we investigate the amplification behavior of the K- α transition of nitrogen at 3.2 nm (395 eV) from radiative transfer calculations coupled with kinetics modeling of the ion population densities. We show that the saturation regime may be experimentally achieved by using PW-class laser-accelerated electron bunches. Finally, we show that this X-ray laser scheme can be extended to heavier atoms and we calculate pump requirements to reach saturation at 1.5 nm (849 eV) from the K- α transition of neon. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-4912-1 Authors M. Ribière, CEA, DAM, GRAMAT, 46500 Gramat, France S. Sebban, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France S. Jacquemot, LULI, Ecole Polytechnique, CEA, UPMC Université Paris VI, 91128 Palaiseau, France B. G. Chéron, CORIA, UMR, CNRS 6614, Saint Etienne du Rouvray, 76801 France K. Ta Phuoc, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France J. Gautier, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France J. Grunenwald, CEA, DAM, GRAMAT, 46500 Gramat, France P. Ribeiro, CEA, DAM, GRAMAT, 46500 Gramat, France M. Kozlova, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France P. Zeitoun, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France A. Rousse, LOA, ENSTA ParisTech, Ecole Polytechnique, UMR CNRS 7639, Chemin de la Hunière, 91761 Palaiseau, France Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    The e-ph coupling may be of the different strength for different electronic bands. If coupling is strong enough for one or more bands, polaronic effects practically decouple these bands from the rest. Single ions being dressed by strong e-ph interactions move in the local potentials having two or more minima, and hence, can be viewed as the system of the Ising spins. Intersite interactions via the RKKY-type exchange by the electron-hole pairs tend to order the latter thus providing the CDW instability mechanism with a structural vector, Q that has nothing in common with the Fermi surfaces parameters. Among the most typical manifestations of such strong e-ph coupling in the system are large characteristic energy scales significantly exceeding the temperatures for the onset of the CDW phase. The available experimental data support interpretation of properties of the transition-atoms-dichalcogenides and the compounds of the A15 group in terms of the local polaronic effects. Content Type Journal Article Category Complex Systems Pages 1-7 DOI 10.1007/s10948-012-1448-x Authors Lev P. Gor’kov, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    This survey provides a brief account for the start of organic superconductivity motivated by the quest for high T c superconductors and its development since the 1980s. Besides superconductivity found in 1D organics in 1980, progresses in this field of research have contributed to better understand the physics of low-dimensional conductors highlighted by the wealth of new remarkable properties. Correlations conspire to govern the low-temperature properties of the metallic phase. The contribution of antiferromagnetic fluctuations to the interchain Cooper pairing proposed by the theory is borne out by experimental investigations and supports superconductivity emerging from a non-Fermi-liquid background. Quasi-one-dimensional organic superconductors can therefore be considered as simple prototype systems for the more complex high T c materials. Content Type Journal Article Category Superconductivity Pages 1-23 DOI 10.1007/s10948-012-1475-7 Authors Denis Jérome, Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The possible relationship between Kondo lattices an superconductivity is discussed for the case of granular superconductors, based on the empirical evidence that they display strong correlation effects near a metal to insulator transition. Content Type Journal Article Category Complex Systems Pages 1-4 DOI 10.1007/s10948-012-1453-0 Authors Guy Deutscher, School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978 Israel Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung: Jacques Friedel and Metallurgy Content Type Journal Article Category Metallurgy, Dislocations, Strains Pages 1-2 DOI 10.1007/s10948-012-1471-y Authors Georges Saada, Laboratoire D’Etude des Microstructures, Onera, 92322 Chatillon, France Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Mn 3 O 4 nanoparticles were synthesized via an ionic liquid (IL) assisted process at room temperature, which is rather difficult to achieve by other techniques. The synthesized product was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetry (TG), and vibrating sample magnetometry (VSM). The prepared material showed a high purity, while crystallite size and particle size agree well with each other, 17±2 and 19±3 nm, respectively, revealing nearly single crystalline character of nanoparticles. The product contains 4 wt% of adsorbed water and ionic liquid. This method provides a facile, one-step, and low-cost route for the synthesis of nanostructures of metal oxides. In addition, [BMIM]BF 4 could be collected and reused for subsequent reactions. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1451-2 Authors Merva Günay, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey Abdülhadi Baykal, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey Muhammet S. Toprak, Functional Materials Division, Royal Institute of Technology, 16440 Stockholm, Sweden Hüseyin Sözeri, TUBITAK-UME, National Metrology Institute, PO Box 54, 41470 Gebze-Kocaeli, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Screening of the Coulomb interaction accounting for the Friedel oscillations in the structures with multicomponent low-dimensional electron plasma is considered. Calculations are made for nanotubes, double quantum wells (DQW) and superlattices. We consider also screening of an impurity potential by neutral particles—indirect dipolar excitons, as well as Friedel oscillations in a hybrid electron–exciton system. Content Type Journal Article Category Nanostructures; Low dimensional systems Pages 1-11 DOI 10.1007/s10948-012-1437-0 Authors A. V. Chaplik, Institute of Semiconductor Physics, 630090 Novosibirsk, Russia V. M. Kovalev, Institute of Semiconductor Physics, 630090 Novosibirsk, Russia L. I. Magarill, Institute of Semiconductor Physics, 630090 Novosibirsk, Russia R. Z. Vitlina, Institute of Semiconductor Physics, 630090 Novosibirsk, Russia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The production of ions via laser ablation for the loading of radiofrequency (RF) ion traps is investigated using a nitrogen laser with a maximum pulse energy of 0.17 mJ and a peak intensity of about 250 MW/cm 2 . A time-of-flight mass spectrometer is used to measure the ion yield and the distribution of the charge states. Singly charged ions of elements that are presently considered for the use in optical clocks or quantum logic applications could be produced from metallic samples at a rate of the order of magnitude 10 5 ions per pulse. A linear Paul trap was loaded with Th + ions produced by laser ablation. An overall ion production and trapping efficiency of 10 −7 to 10 −6 was attained. For ions injected individually, a dependence of the capture probability on the phase of the RF field has been predicted. In the experiment this was not observed, presumably because of collective effects within the ablation plume. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-4884-1 Authors K. Zimmermann, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany M. V. Okhapkin, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany O. A. Herrera-Sancho, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany E. Peik, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We have demonstrated proof-of-principle of an incoherent ArF ∗ emission source with a quasi-point emission geometry using a laser-produced plasma in an Ar/F 2 /He/Ne mixed gas. The VUV emission characteristics, such as the emission size, were dependent on those of the plasma-initiating laser. The average emission power was 10 μW at a repetition rate of 10 Hz at 193 nm. The average power conversion efficiency of the 193-nm emission from the plasma-initiating Nd:YAG laser was 6.3×10 −6 . The average emission power at 193 nm was proportional to that of the plasma-initiating laser, indicating the scaling of the emission source. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-4906-z Authors M. Kaku, Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, 889-2192 Japan Y. Sato, Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, 889-2192 Japan S. Kubodera, Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, 889-2192 Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Measurements of 3-pentanone fluorescence quantum yield (FQY) over a wide range of temperatures and pressures in air and nitrogen bath gases are reported and a comprehensive FQY model in support of quantitative planar laser-induced fluorescence diagnostics at elevated pressures and temperatures is presented. Measurements were made of the FQY for 20 mbar of 3-pentanone in nitrogen and air for pressures between 1 and 25 bar in a high-pressure and high-temperature cell for excitation wavelengths of 248, 266, 277, and 308 nm. The measurements were performed in nitrogen from 298 to 745 K and in air from 298 to 567 K. The 3-pentanone FQY data were used to optimize FQY model parameters, including the oxygen and nitrogen quenching rates and vibrational relaxation cascade parameters for nitrogen and oxygen. This work introduces vibrational energy dependence for cascade parameters, as well as a nitrogen quenching rate. The new 3-pentanone FQY model agrees with the measurements within 10%, as well as with fluorescence signal measurements from optical internal combustion engines at pressures and temperatures up to 28 bar and 1100 K. Content Type Journal Article Pages 1-14 DOI 10.1007/s00340-012-4901-4 Authors B. H. Cheung, High Temperature Gasdynamics Laboratory, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA R. K. Hanson, High Temperature Gasdynamics Laboratory, Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Through the study of photoluminescence spectra, fluorescence decay curves, concentration-dependent luminescence and low temperature luminescence, the energy transfer from isolated group to Yb 3+ is investigated in Yb 3+ doped YP 0.9 V 0.1 O 4 . The experimental results show that the energy transfer from group to Yb 3+ is very efficient. Cooperative energy transfer, through which one high-energy photon absorbed by group is converted to two near-infrared photons emitted by Yb 3+ ions, is proposed to be the energy transfer process. This efficient ultra-violet to near-infrared downconversion could have potential application in improving the efficiency of silicon-based solar cell. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-4892-1 Authors X. T. Wei, Department of Physics, University of Science and Technology of China, Hefei, 230026 China G. Jiang, Department of Physics, University of Science and Technology of China, Hefei, 230026 China K. Deng, Department of Physics, University of Science and Technology of China, Hefei, 230026 China C. Duan, Department of Physics, University of Science and Technology of China, Hefei, 230026 China Y. Chen, Department of Physics, University of Science and Technology of China, Hefei, 230026 China M. Yin, Department of Physics, University of Science and Technology of China, Hefei, 230026 China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Ion chains consisting of different species play an important role in new applications in quantum information processing as well as in optical frequency standards. We demonstrate generation and stabilization of ion chains consisting of Ca + and In + . The Ca + chains with In + located at specified positions are synthesized using resonant photo-ionization, real-time imaging and trap field control techniques. A specific configuration of an ion chain is stabilized by destabilizing other configurations via selective excitation of vibrational modes using amplitude modulation on the cooling laser beam. New approaches to an indium ion optical clock are proposed using the ions chains. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-4909-9 Authors K. Hayasaka, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho Nishi-ku, Kobe, 651-2492 Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Raman frequency conversion of high average power pulsed Nd:YAG laser radiation into the near IR spectral region in a barium nitrate Raman laser was studied with the emphasis on thermal effects inside the Raman-active medium. The probe-beam technique together with numerical reconstruction, done by integrating the transient heat conduction and paraxial wave equations, revealed dynamics of the induced distortions featuring high-order optical aberrations. By utilizing the Zernike expansion of the reconstructed phase profile and implementing a special focusing geometry of the pump beam, partial compensation of the distortions was realized in a stable configuration of the Raman cavity. Generation of the first-, second-, and third-order Stokes radiation with output power of 17, 9.5, and 5.5 W corresponding to a quantum conversion efficiency of 32, 21, and 13% is reported. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-012-4873-4 Authors R. Chulkov, B.I. Stepanov Institute of Physics, National Academy of Science of Belarus, Nesalezhnasti Ave. 68, 220072 Minsk, Belarus V. Lisinetskii, Engineering Physics, University of Applied Sciences Wildau, Bahnhofstr., 1, 15745 Wildau, Germany O. Lux, TU Berlin—Institut für Optik und Atomare Physik, Str.d.17.Juni 135, 10623 Berlin, Germany H. Rhee, TU Berlin—Institut für Optik und Atomare Physik, Str.d.17.Juni 135, 10623 Berlin, Germany S. Schrader, Engineering Physics, University of Applied Sciences Wildau, Bahnhofstr., 1, 15745 Wildau, Germany H. J. Eichler, TU Berlin—Institut für Optik und Atomare Physik, Str.d.17.Juni 135, 10623 Berlin, Germany V. Orlovich, B.I. Stepanov Institute of Physics, National Academy of Science of Belarus, Nesalezhnasti Ave. 68, 220072 Minsk, Belarus Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A silver nanoparticle ensemble was prepared under ultrahigh vacuum (UHV) conditions by Volmer–Weber growth on a quartz substrate for surface-enhanced Raman scattering (SERS) investigations of pyrene molecules. To tune the surface plasmon resonance frequency in the vicinity of the excitation wavelength of 488 nm of the diode laser, the morphology of the silver nanoparticles was optimized. The substrates were mounted in a flow-through cell as part of the optical Raman set-up. A microsystem diode laser generates two slightly different emission wavelengths ( λ =487.61 nm and λ =487.91 nm) with a spectral width 〈10 pm and an optical power of 20 mW, i.e. SERS experiments are possible but also shifted excitation Raman difference spectroscopy (SERDS) can be carried out. For trace analysis of pyrene in water we demonstrate SERS/SERDS experiments which lead to a limit of detection of 2 nmol/l for pyrene. These results suggest that with silver nanoparticle ensembles excited at their plasmon resonance at 488 nm combined SERS/SERDS measurements can be effectively performed for in-situ trace analysis of pollutant chemicals in water. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-011-4866-8 Authors R. Ossig, Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology—CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany Y.-H. Kwon, Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany F. Hubenthal, Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology—CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany H.-D. Kronfeldt, Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    In this paper, a series of iron (Fe) containing nanoparticles were prepared by employing PAMAM (Poly(amidoamine), dendrimers with different generations (G0–G3) as templates and sodium borohydride as a reducing agent. The products have been characterized by TEM, FT-IR, XRD, VSM, TGA, and XPS. XRD analysis reveal low crystallinity of formed particles within the dendrimers, however, crystallinity of the nanoparticles was observed to increase with increasing generation of dendrimers. Dominant phases were determined as magnetite (Fe 3 O 4 or maghemite, γ -Fe 2 O 3 ). XPS analysis revealed the chemical composition of nanoparticles as iron oxide which indicated the oxidation of Fe species subsequent to the reduction process, in agreement with XRD analysis. The magnetization curves have superparamagnetic nonhysteretic characteristic at lower fields and with nonsaturation characteristic at high fields. Magnetic evaluation of samples with the 20:1 molar ratio of Fe:PAMAM showed decreasing superparamagnetic character and decreasing saturation magnetisation with increasing generation of dendrimers. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s10948-012-1454-z Authors A. Baykal, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey M. S. Toprak, Functional Materials Division, Royal Institute of Technology—KTH, 16440 Stockholm, Sweden Z. Durmus, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey M. Senel, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey H. Sozeri, TUBITAK-UME, National Metrology Institute, PO Box 54, Gebze, 41700 Kocaeli, Turkey A. Demir, Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    In this study, superconducting samples of type Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10− δ added by SnO 2 and In 2 O 3 in nano-scale were prepared by a solid-state reaction technique. The concentrations of both SnO 2 and In 2 O 3 were 0.0, 0.1, 0.2, 0.4, 0.6 and 1.0 wt% of the sample’s total mass. The prepared samples were characterized using X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) for phase analysis and microstructure examination. The elemental content of the prepared samples was determined using energy dispersive X-ray (EDX) and particle induced X-ray emission (PIXE). The results of elemental content, determined from EDX and PIXE, were compared and discussed. In addition, The oxygen content of these samples was obtained using non Rutherford backscattering spectroscopy (RBS) at 3 MeV proton beam. It was found that the Oxygen-content of (Cu 0.5 Tl 0.5 )-1223 phase was not affected by both SnO 2 and In 2 O 3 nano-oxides addition. The electrical resistivity of the prepared samples was measured by the conventional four-probe technique from room temperature down to the zero superconducting transition temperature ( T 0 ). An increase in the superconducting transition temperature T c from 106 to 119 K was observed as x was varied from 0.0 to 0.6 wt% for (SnO 2 ) x Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10− δ , followed by a systematic decrease with increasing nano-SnO 2 addition. On the other hand, the T c values for (In 2 O 3 ) x Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10− δ show a small variation with  x . Moreover, the variation rate of T c with x , for both nano-additions, was found to be directly proportional to the variation of the volume fraction of the prepared samples. Content Type Journal Article Category Original Paper Pages 1-14 DOI 10.1007/s10948-012-1465-9 Authors N. H. Mohammed, Physics Department, Faculty of Science, Alexandria University, Moharam Bek, P.O. Box, 21511 Alexandria, Egypt R. Awad, Physics Department, Faculty of Science, Alexandria University, Moharam Bek, P.O. Box, 21511 Alexandria, Egypt A. I. Abou-Aly, Physics Department, Faculty of Science, Alexandria University, Moharam Bek, P.O. Box, 21511 Alexandria, Egypt I. H. Ibrahim, Physics Department, Faculty of Science, Alexandria University, Moharam Bek, P.O. Box, 21511 Alexandria, Egypt M. Roumié, Accelerator Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, Airport Road, P.O. Box 11, 8281 Beirut, Lebanon M. Rekaby, Physics Department, Faculty of Science, Alexandria University, Moharam Bek, P.O. Box, 21511 Alexandria, Egypt Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Electronic structures of ZnO-based dilute magnetic semiconductors (DMS) are investigated within the self-interaction-corrected local density approximation (SIC-LDA). These results are compared with those calculated within the standard LDA. The Korringa–Kohn–Rostoker method combined with coherent potential approximation has been used. We find the differences between LDA and SIC-LDA calculations, in the band-gap energy. The energetic position of the Zn 3d bands and the description of the transition-metal d bands, have been studied. In contrast to the standard LDA calculations, the results obtained within SIC-LDA are in good agreement with the experimental ones. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s10948-012-1470-z Authors E. Salmani, LMPHE (URAC 12), Departement de Physique, Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco A. Benyoussef, LMPHE (URAC 12), Departement de Physique, Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco H. Ez-Zahraouy, LMPHE (URAC 12), Departement de Physique, Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco E. H. Saidi, LPHE, Departement de Physique, Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Optical and photocatalytic properties of ZnS, ZnS:Mn 2+ (20 and 30 wt%) and ZnS:Sm 3+ (20 and 30 wt%) samples formed by three coatings, were studied. The layers were deposited on glass substrate by the sol-gel dip coating process. The catalytic activity of the samples was determined by means of the photodecomposition of methylene blue under Ultra Violet and visible light irradiations. The Fourier Transform Infrared (FTIR) spectrum of ZnS shows the presence of OH, N–H, N–C and S–H groups. The last two groups suggest the formation of a thiocyanuric group (NCS − ) on the surface of the sample which enables the photocatalytic activity of undoped ZnS and doped ZnS under visible light irradiation. Content Type Journal Article Category Original Paper Pages 1-4 DOI 10.1007/s10948-012-1432-5 Authors E. Gómez-Barojas, CIDS-IC, Benemérita Universidad Autónoma de Puebla, Puebla, Pue 72570, Mexico E. Sánchez-Mora, Instituto de Física, BUAP. Apdo, Postal J-48, Puebla, Pue 72570, Mexico C. Castillo-Abriz, Instituto de Física, BUAP. Apdo, Postal J-48, Puebla, Pue 72570, Mexico E. Flores-Rodríguez, Instituto de Física, BUAP. Apdo, Postal J-48, Puebla, Pue 72570, Mexico R. Silva-González, Instituto de Física, BUAP. Apdo, Postal J-48, Puebla, Pue 72570, Mexico Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    An off-equilibrium redox condition study of Mn 2+ and Mn 4+ ions added to the batch is reported for the case of the preparation of the barium aluminoborate glasses, by considering that the out of equilibrium reactions started already on the melt. It is shown that for lower dopant concentrations the relative concentrations of the oxidation states of the manganese are found out of equilibrium up to the added amount of 0.3 mol% of MnO 2 , but on doping with MnO, the equilibrium state is achieved at the MnO added amount of 0.07 mol%. The change of the redox condition of the manganese ions toward the equilibrium was studied by tracking the Mn 2+ amount as a function of the doping concentration in the two cases of MnO and MnO 2 . Content Type Journal Article Category Original Paper Pages 1-4 DOI 10.1007/s10948-012-1457-9 Authors J. M. Giehl, Institute of Physics Gleb Wataghin, University of Campinas, Campinas, SP, Brazil A. R. Miranda, Institute of Physics Gleb Wataghin, University of Campinas, Campinas, SP, Brazil W. M. Pontuschka, Institute of Physics, University of São Paulo, São Paulo, SP, Brazil M. Navarro, Institute of Physics, University of São Paulo, São Paulo, SP, Brazil Z. M. Da Costa, Institute of Exact Science, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    In this work, we report synthesis and characterization of the new La 2 SrCo 2 FeO 9 triple perovskite material. The samples were produced by the solid-state reaction method. The analyses of the XRD patterns were made by Rietveld refinement through the GSAS code. The results reveal that the material crystallizes in an orthorhombic complex perovskite, space group Immm (#71) with lattice parameters a =5.4314(3) Ǻ, b =5.4583(3) Ǻ and c =7.7018(2) Ǻ. SEM micrographs evidence a strongly diffused granular morphology with mean grain size of 2 μm and the EDX spectra show that the chemical composition of samples are in good agreement with the nominal values of the stoichiometric formula. 57 Fe Mössbauer spectroscopy recorded at 300 K reveals two sites in concordance with the X-ray diffraction measurements, and its valence state is +3, as determined from the isomer shift found. At 4.2 K magnetic ordering with canting of the Fe moments is found. Measurements of the magnetization as a function of temperature permitted us to determine the ferromagnetic characteristic of material with an effective magnetic moment of 9.7 μ B . Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1425-4 Authors Julio C. Albornoz, Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC, Colombia David A. Landínez Téllez, Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC, Colombia Jairo Roa-Rojas, Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC, Colombia Julian A. Munévar, Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ, Brasil Elisa Baggio-Saitovich, Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ, Brasil Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    In the present paper, the effect of non-polar longitudinal optical phonons on domain wall resistance has been studied using the semiclassical approach. The analysis has been based on the Boltzmann transport equation, within the relaxation time approximation. We have determined the magnetoresistance of domain wall in nanowires based on diluted magnetic semiconductors. The modulation of the exchange and the impurity interactions by lattice vibrations, and the hole–phonon interaction are considered. The results indicate that the scattering role of phonons becomes significant by increasing temperature, which leads to the resistivity enhancement. It is also found that the magnetic impurities play an impressive role in enhancing the contribution of the domain wall in the resistance. In providing room temperature spintronics devices, understanding the effects of phonons and magnetic impurities on the domain wall resistance is crucial. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1487-3 Authors R. Majidi, Department of Physics, Shahid Rajaee Teacher Training University, 16788-15811 Tehran, Iran M. M. Tehranchi, Department of Physics, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Iran A. Phirouznia, Department of Physics, Azarbaijan University of Tarbiat Moallem, 53714-161 Tabriz, Iran Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Thick films of ((Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O x ) 1− y (La 0.7 Sr 0.3 MnO 3 ) y [(Bi2223) 1− y (LSMO) y ] composites ( y =0.01, 0.03, 0.05) are deposited by means of a simple melting-quenching-annealing method onto (001)-oriented LaAlO 3 (LAO) substrates. The constituent compounds Bi2223 and LSMO are prepared by standard solid-state reaction and sol–gel method, respectively. Measurements of the dependence of the magnetization on the temperature show the presence of superconducting and ferromagnetic phase below ∼54 K and ∼370 K, respectively. Current–voltage measurements on composites with y =0.01, 0.03 show that the superconducting critical current drop dramatically from I c ≈350 mA at T =15 K to zero at T ≈0.5 T c (∼25 K). The dependence of the magnetization on the external magnetic field applied in-plane or out-of-plane at 5 K displays well defined hysteresis loops, which correspond to the superconducting, diamagnetic phase. For T 〉 T c , the ferromagnetic loop of LSMO is observed. The critical current density, J c , was determined for samples with y =0.01 and 0.05 by applying Kim’s model to the superconducting, diamagnetic hysteresis recorded at 5 K. The calculated values for J c ( B ) resulted to be smaller than those obtained for individual bulk Bi2223 samples due, probably, to the presence of LSMO particles whose ferromagnetic domains compete with the superconducting diamagnetic phase. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1455-y Authors O. Paredes, Centro de Materiales, Facultad de Ingeniería, Universidad de Nariño, Ciudad Universitaria Torobajo, Pasto, Colombia E. Baca, Grupo de Ingeniería de Nuevos Materiales, Departamento de Física, Universidad del Valle, A.A. 25360 Cali, Colombia O. Morán, Laboratorio de Materiales Cerámicos y Vítreos, Departamento de Física, Universidad Nacional de Colombia, Sede Medellín, A.A. 568, Medellín, Colombia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The interaction between a cylindrical magnet and a superconducting hollow cylinder in the Meissner state was analyzed using a dipole–dipole model. Analytical expression of the levitation force was derived as a function of the magnetic moment, radius of the magnet, radius, and thickness of the superconductor sample. The effect of the magnet’s dimensions on the levitation force was studied. The obtained results show that there is strong dependence of the levitation force on the magnetic dipole orientation at a small magnet–superconductor distance. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1483-7 Authors M. K. Alqadi, Department of Physics, Jordan University of Science and Technology, Irbid, Jordan F. Y. Alzoubi, Department of Physics, Jordan University of Science and Technology, Irbid, Jordan S. M. Saadeh, Department of Physics, Jordan University of Science and Technology, Irbid, Jordan H. M. Al-Khateeb, Department of Physics, Jordan University of Science and Technology, Irbid, Jordan N. Y. Ayoub, Dean of Graduate Studies, German Jordanian University, Amman, Jordan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The first-principles full potential linearized augmented plane wave method within spin-polarized density functional theory was used to investigate the structural, electronic, and magnetic properties of NaX compounds in the NiAs, rocksalt (RS), and zincblende (ZB) phases. The results showed that in all compounds, the stable state phase is a nonmagnetic (NM) NiAs structure except for NaO in which the stable state phase is a ferromagnetic (FM) RS structure. The ZB NaX (X=O, S, Se, Te, and Po) and RS NaX (X=O, S, and Se) structures are half-metallic (HM) ferromagnets with an integer magnetic moment of 1 μ B per formula unit. The half-metallicity originates from hybridization between X p and Na s and p states. The ZB NaO compound is a very robust half-metal which has the HM band gap of 1.25 eV and maintains HM characteristic up to above 40% of the lattice constant contraction. The half-metallicity is also found up to the lattice constant contraction of about 26.3%, 19.6%, 10.4%, and 7.5% for ZB NaS, NaSe, NaTe, and NaPo and 27.1%, 6.4%, and 1.7% for RS NaO, NaS, and NaSe, respectively. The robustness of half-metallicity with respect to the lattice contraction in the HM NaX compounds and their compatibility with the binary semiconductors make them suitable candidates in spintronic applications. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s10948-012-1480-x Authors F. Ahmadian, Department of Physics, Shahreza Branch, Islamic Azad University, Shahreza, Iran Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    In order to check the solubility of Zn in the (Sr 1− x Zn x )CoO 3 perovskite structure and their research findings, several polycrystalline samples have been prepared under wide extreme synthesis conditions at 6 GPa/1300–1650 °C. While 0.05≤ x ≤0.3 compositions revealed single phased cubic structure materials, x 〉0.3 showed multi-phased materials for (Sr 1− x Zn x )CoO 3 system. Like other substituted perovskite cobalt oxide systems (Ca, Y, Ho and Ce), the transport properties of the present materials show rather sizable changes with respect to ‘ x ’, although there are insignificant variations in lattice parameter and in Curie temperature, T c . All the present samples show soft ferromagnetism with T c in the range of 272–285 K for 0.05≤ x ≤0.3. The effective paramagnetic moment, P eff determined from the paramagnetic region decreases upon the substitution of Zn for Sr-site. These P eff (3.3–2.8 μ B /Co) values for 0.05≤ x ≤0.3 compositions seem to suggest that the Co 4+ lie in intermediate spin (IS) state for the present (Sr 1− x Zn x )CoO 3 series, although they are slightly smaller than those expected for IS-Co 4+ ; P eff =3.87 μ B /Co. The electrical resistivity is found to increase with increase of ‘ x ’ for the investigated samples. The temperature and field dependence of both positive and negative magnetoresistance (MR) are noted for the Zn substituted samples. About 5% of –MR is observed for x =0.05 sample around the transition temperature (280 K) under the field strength difference, Δ H =90 kOe. The present research findings are compared with our previous results on different perovskite cobalt oxides. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s10948-012-1488-2 Authors S. Balamurugan, Advanced Nanomaterials Research Laboratory, Department of Nanotechnology, Noorul Islam Centre for Higher Education, Kumaracoil, Thuckalay, 629 180 Tamilnadu, India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The determination of their critical current density in the whole range of the temperature below T c is of first importance to understand the physical processes occurring in superconducting films. We describe here a technique suitable for square films based on the measurement of the magnetic moment due to the currents persisting in the superconductor after the application of a perpendicular high magnetic field. Typically, with a SQUID magnetometer, the measurement time in the whole range of temperature with a 1 K interval is of 2 hours only by this technique. An intriguing aspect of the obtained results is that they are much more accurate if the current lines are supposed to be circular than if we suppose, as suggested by theoretical considerations and magnetooptical observations that they have the sample symmetry. Content Type Journal Article Category Original Paper Pages 1-4 DOI 10.1007/s10948-012-1782-z Authors Conor McLoughlin, CRISMAT-ENSICAEN, UMR-CNRS 6508, 14050 Caen, France Pierre Bernstein, CRISMAT-ENSICAEN, UMR-CNRS 6508, 14050 Caen, France Yohann Thimont, CRISMAT-ENSICAEN, UMR-CNRS 6508, 14050 Caen, France J. Siejka, INSP, UMR-CNRS 7588, 75251 Paris, France Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    We describe a method to monitor the distance between two tips of a scanning near-field optical microscope setup. The interaction between the two tips, caused by shear forces and air pressure oscillations between the tips, makes each oscillating tip perform an additional oscillation at the frequency of the other tip. The interaction is detected by analyzing one of the tuning fork signals with a lock-in amplifier locked at the oscillation frequency of the other tuning fork. The resulting signal, called crosstalk, increases sharply only when the scanning tip comes into the immediate vicinity of the stationary one. This effect allows us to prevent the tips from colliding during scanning. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5182-7 Authors A. E. Klein, Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany N. Janunts, Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany A. Tünnermann, Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany T. Pertsch, Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Supercontinuum (SC) generation in a standard telecom fiber using 1 ns pulses of a 1,550-nm DFB laser amplified in a cascade of erbium and erbium/ytterbium fiber amplifiers is reported. The SC source operated at 200 kHz repetition rate and delivered up to 2 W of average output power in the band of 1,300–2,500 nm with a diffraction limited beam. For the wavelengths over 1,650 nm, the output power of 1.1 W was recorded. The spectrum was very flat with the flatness of 〈5 dB in the wavelength interval of 1.6–2.18 μm. To the best of our knowledge, it is the first report on W-level SC generation obtained only in a standard single-mode fiber (SMF-28) with almost the entire spectrum in the eye-safe spectral region (λ 〉 1.4 μm) permitted by silicate glass transparency. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5213-4 Authors Jacek Swiderski, Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Street, 00-908 Warsaw, Poland Maria Maciejewska, Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Street, 00-908 Warsaw, Poland Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We show, for the first time, that step-index silica fibers with a large clad (400 μm core and 720 μm clad) can be used to transmit nanosecond duration pulses in a way that allows reliable (consistent) spark formation in atmospheric pressure air by the focused output light from the fiber. The high intensity (〉100 GW/cm 2 ) of the focused output light is due to the combination of high output power (typical of fibers of this core size) with high output beam quality (better than that typical of fibers of this core size). The high output beam quality, which enables tight focusing, is due to the large clad which suppresses microbending-induced diffusion of modal power to higher order modes owing to the increased rigidity of the core-clad interface. We also show that extending the pulse duration provides a means to increase the delivered pulse energy (〉20 mJ delivered for 50 ns pulses) without causing fiber damage. Based on this ability to deliver high energy sparks, we report the first reliable laser ignition of a natural gas engine including startup under typical procedures using silica fiber optics for pulse delivery. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5189-0 Authors Sachin Joshi, Laser Plasma Diagnostics Laboratory, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA Nick Wilvert, Laser Plasma Diagnostics Laboratory, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA Azer P. Yalin, Laser Plasma Diagnostics Laboratory, Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We evaluate the design of Q-switched microchip lasers to examine the limit of their scaling to shorter picosecond pulses. A numerical model based on the laser rate equations is developed and used to predict the output characteristics of prospective laser designs. Based on the modeled results, we employ a SESAM as a passive Q-switch and thin crystals of Nd:YVO 4 as a gain medium to experimentally demonstrate the production of pulses as short as 22 ps. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5223-2 Authors Alex C. Butler, Department of Physics and Astronomy, MQ Photonics Research Centre, Macquarie University, North Ryde, Sydney, NSW 2109, Australia David J. Spence, Department of Physics and Astronomy, MQ Photonics Research Centre, Macquarie University, North Ryde, Sydney, NSW 2109, Australia David W. Coutts, Department of Physics and Astronomy, MQ Photonics Research Centre, Macquarie University, North Ryde, Sydney, NSW 2109, Australia Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Time-resolved detection of field-free molecular alignment is investigated by phase contrast. The technique based on a 4 f imager operating as an inverted Zernike spatial filter makes it possible to discriminate between positive and negative molecular alignment revivals produced in a linear molecule. The measurements are performed in a way that minimizes the contamination of the signal by the plasma generated during the aligning pulse. The observations are supported by a semi-analytical model, from which the degree of alignment produced at the beam focus is estimated. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5203-6 Authors J. Houzet, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France F. Billard, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France E. Hertz, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France D. Chateau, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France F. Chaussard, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France B. Lavorel, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France O. Faucher, Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We experimentally demonstrate the writing of soliton waveguides in lithium niobate with blue violet light, at λ  = 405 nm. This wavelength, obtained from a low-cost laser diode, allows very fast writing of soliton waveguides when comparing with the writing process using green light (532 nm). For the same writing time, there is a decrease of ~4 orders of magnitude of the light intensity necessary for writing soliton waveguides in blue. The writing process is investigated and characterized by tuning parameters, such as beam intensity, external field and beam polarization. The IR guiding capability of these soliton waveguides is tested by guiding femtosecond laser pulses at λ  = 1,550 nm. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-5202-7 Authors S. T. Popescu, National Institute for Laser, Plasma and Radiation Physics, Bucharest, Magurele, 077125 Romania A. Petris, National Institute for Laser, Plasma and Radiation Physics, Bucharest, Magurele, 077125 Romania V. I. Vlad, National Institute for Laser, Plasma and Radiation Physics, Bucharest, Magurele, 077125 Romania Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A Faraday isolator system with external compensation of thermally induced birefringence was investigated for the case when optical components of the Faraday isolator and the compensator are made of different materials. Simultaneous reduction of thermally induced depolarization and thermal lens in the Faraday isolator based on a TGG crystal was demonstrated experimentally for the first time using an Sm:CaF 2 crystal. A method of compensating thermally induced birefringence without reciprocal polarization rotator was described theoretically and demonstrated in experiments for the first time. It was used as a basis for a new scheme of Faraday isolator with external compensation of thermally induced birefringence. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-012-5183-6 Authors Ilya L. Snetkov, Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Street, 603950 Nizhny Novgorod, Russia Oleg V. Palashov, Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Street, 603950 Nizhny Novgorod, Russia Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We report on the generation of tunable light around 400 nm by frequency-doubling ultrashort laser pulses whose spectral phase is modulated by a sum of sinusoidal functions. The linewidth of the ultraviolet band produced is narrower than 1 nm, in contrast to the 12 nm linewidth of the non-modulated incident spectrum. The influence of pixellation of the liquid crystal spatial light modulator on the efficiency of the phase-modulated second harmonic generation is discussed. Content Type Journal Article Category Rapid Communication Pages 1-5 DOI 10.1007/s00340-012-5181-8 Authors J. P. Siqueira, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP 13560-970, Brazil A. R. de Oliveira, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP 13560-970, Brazil L. Misoguti, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP 13560-970, Brazil S. C. Zilio, Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP 13560-970, Brazil Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We demonstrated the lasing of Ne-like Ar 46.9 nm pumped by capillary discharge with the delay time between pre-pulse and main-pulse ranging from 2 to 130 μs. Results show that the laser output reduced significantly when the delay time is much longer than 12 μs. The temporal evolution of spontaneous radiation emitted from pre-ionized plasma implies that the observed reduction of the laser output is caused by the axial non-uniformity of pre-ionized plasma density and the decrease of pre-ionized plasma density. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-5190-7 Authors Shan Jiang, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Yong-peng Zhao, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Yao Xie, State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 Jilin, China Miao Xu, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Huai-yu Cui, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Han Wu, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Yang Liu, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Qiang Xu, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Qi Wang, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin, 150080 Heilongjiang, China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A passive mode-locked fiber laser-delivered 13 ps pulse is saturatedly amplified with a four-stage amplifier chain. 125 W high power all-fiber picoseconds pulse laser is demonstrated in a 15-μm fiber core, and the optical-to-optical conversion efficiency of the main amplifier is up to 86.12 %. A home-made (6 + 1) × 1 fiber combiner is used to couple the pump light and signal light into the gain double cladding fiber. In order to suppress the nonlinear effects in high-power picosecond fiber amplifiers, the repetition rate of the seed pulse is increased from 60 MHz to ~1 GHz; also the gain fibers are advisably selected. The amplified output spectrum is symmetrically broadened to several nanometers due to self-phase modulation (SPM). No stimulated Raman scattering (SRS), amplified spontaneous emission (ASE) and residual pump light are observed and the optical signal-to-noise ratio is more than 30 dB. The all-fiber picoseconds MOPA laser in this report can be easily performed with the conventional fiber handing equipments, and it has great potential to be applied as pump source in the fields of optical parametric oscillator, laser frequency-doubling and supercontinuum generation. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5119-1 Authors H. W. Chen, College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 People’s Republic of China Y. Lei, College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 People’s Republic of China S. P. Chen, College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 People’s Republic of China J. Hou, College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 People’s Republic of China Q. S. Lu, College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 People’s Republic of China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Continuous-wave (CW) and passively Q-switching laser performance of the Yb:CNGG and Yb:CLNGG disordered garnet crystals are compared. CW output powers of 6.3 and 7.5 W are generated from the Yb:CNGG and Yb:CLNGG lasers, with slope efficiencies measured to be 63 and 74 %, respectively. In passively Q-switched operation, the average output power reaches 2.0 and 3.1 W, with slope efficiencies of 56 and 65 %, for the Yb:CNGG and Yb:CLNGG lasers, respectively. Laser pulses of 9.5 ns in duration are generated with the two Yb lasers, with the highest pulse energy and peak power amounting to 166.7 μJ and 17.5 kW for the Yb:CNGG laser, and 133.0 μJ and 14.0 kW for the Yb:CLNGG laser. In respects of efficient laser operation and power scaling, the Yb:CLNGG proves to be advantageous over Yb:CNGG, whereas the Yb:CNGG is superior to Yb:CLNGG in energy storage capacity. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5212-5 Authors Junhai Liu, College of Physics, Qingdao University, Ning-Xia Road 308, Qingdao, 266071 China Yong Wan, College of Physics, Qingdao University, Ning-Xia Road 308, Qingdao, 266071 China Zhichao Zhou, College of Physics, Qingdao University, Ning-Xia Road 308, Qingdao, 266071 China Xueping Tian, College of Physics, Qingdao University, Ning-Xia Road 308, Qingdao, 266071 China Wenjuan Han, College of Physics, Qingdao University, Ning-Xia Road 308, Qingdao, 266071 China Huaijin Zhang, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    The formation and evolution of laser-induced post-solitons in near-critical density plasma are studied using the two-dimensional theoretical model and particle in cell simulation. The study shows that a considerable part of laser energy can penetrate plasma, which is then trapped in an empty cavity bounded by overdense plasma peaks. The self-trapped electromagnetic fields remain as a half-cycle standing wave. The amplitude of these electromagnetic fields peaks at the cavity center and vanishes at the boundary. As the cavity expands slowly, the field amplitude decreases, and the oscillation frequency is reduced to merely a small faction of laser frequency. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5140-4 Authors Shixia Luan, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800 China Wei Yu, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800 China Wenwu Xu, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, 116023 China Masakatsu Murakami, Institute of Laser Engineering, Osaka University, Osaka, 565-0871 Japan Hongbin Zhuo, College of Science, National University of Defense Technology, Changsha, 410073 China Jingwei Wang, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800 China Xin Wang, Rice University, Houston, TX 77005-1892, USA Huichun Wu, Los Alamos National Laboratory, Los Alamos, NM 87545, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    In this work, we investigate experimentally and theoretically limitations of highly efficient high-power single-pass second-harmonic generation process in a quasi-phase matched magnesium oxide-doped lithium niobate ridge waveguide due to structural imperfections, optical absorption and resulting heat generation. With the distributed Bragg reflector diode laser emitting at 1,061 nm, applied in the presented bench-top experiment, a coupling efficiency into the ridge waveguide nonlinear device of 86 % is realized. An internal normalized conversion efficiency of 375 % (Wcm 2 ) - 1 is determined. A maximum second-harmonic power of 386 mW is reached at a corresponding opto-optical and electro-optical conversion efficiency of 38 and 9.5 %, respectively. A saturation of the conversion efficiency at a high power level as well as its dependency on the nonlinear device structure inhomogeneity are confirmed experimentally. With a theoretical model incorporating geometrical inhomogeneity, linear and nonlinear absorption and resulting heat load the second-harmonic generation in a ridge waveguide can be simulated realistically. Increased values of nonlinear absorption coefficients, higher than until now reported, lead to a very good agreement between theoretical and experimental results. Moreover, according to the simulation, structural inhomogeneities can enhance the SHG conversion efficiency at high output powers. Content Type Journal Article Pages 1-10 DOI 10.1007/s00340-012-5184-5 Authors Daniel Jedrzejczyk, Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany Reiner Güther, Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany Katrin Paschke, Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany Götz Erbert, Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany Günther Tränkle, Ferdinand-Braun-Institut, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We report on studies on the light-shift in caesium miniature atomic clocks based on coherent population trapping (CPT) using a micro-fabricated buffer-gas cell (MEMS cell). The CPT signal is observed on the Cs D1-line by coupling the two hyperfine ground-state Zeeman sublevels involved in the clock transition to a common excited state, using two coherent electromagnetic fields. These light fields are created with a distributed feedback laser and an electro-optical modulator. We study the light-shift phenomena at different cell temperatures and laser wavelengths around 894.6 nm. By adjusting the cell temperature, conditions are identified where a miniature CPT atomic clock can be operated with simultaneously low temperature coefficient and suppressed light-shift. The impact of the light-shift on the clock frequency stability is evaluated. These results are relevant for improving the long-term frequency stability of CPT-based Cs vapour-cell clocks. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-012-5121-7 Authors D. Miletic, Laboratoire Temps-Fréquence (LTF), Institut de Physique, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland C. Affolderbach, Laboratoire Temps-Fréquence (LTF), Institut de Physique, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland M. Hasegawa, FEMTO-ST, CNRS et Université de Franche-Comté, 32 avenue de l’observatoire, 25044 Besançon cedax, France R. Boudot, FEMTO-ST, CNRS et Université de Franche-Comté, 32 avenue de l’observatoire, 25044 Besançon cedax, France C. Gorecki, FEMTO-ST, CNRS et Université de Franche-Comté, 32 avenue de l’observatoire, 25044 Besançon cedax, France G. Mileti, Laboratoire Temps-Fréquence (LTF), Institut de Physique, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We demonstrate laser nitrogen isotope separation, which is based on field-free alignment and angular-dependent ionization of 14 N 2 and 15 N 2 isotopologues. A linearly polarized short laser pulse ( λ  ~ 795 nm, Δ τ  ~ 60 fs) creates rotational wave packets in the isotopologues, which periodically revive with different revival times as a result of different moments of inertia. Another linearly polarized short laser pulse ( λ  ~ 795 nm, Δ τ  ~ 60 fs) ionizes one of the isotopologues selectively as a result of their different angular distributions. In the present experiments, the ion yield ratio R [= I ( 15 N 2 + )/ I ( 14 N 2 + )] can be changed in the range from 0.85 to 1.22, depending on the time delay between the two laser pulses. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5222-3 Authors Hiroshi Akagi, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan Tatsuya Kasajima, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan Takayuki Kumada, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan Ryuji Itakura, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan Atsushi Yokoyama, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan Hirokazu Hasegawa, Department of Integrated Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902 Japan Yasuhiro Ohshima, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, 444-8585 Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Nanosize three-dimensional (3D) dark spots with a light shell in enhanced local optical fields generated by a plasmonic metal-coated conical dielectric probe with a nano-rod are investigated numerically. The 3D dark spots are due to interference among plasmon-enhanced local fields. It is found that two kinds of 3D dark spots are generated in the free space in the vicinity of the nano-rod. One is generated near the rod end and has a disk shape. The other is generated around the nano-rod and has a toroidal shape. Both kinds of 3D dark spots have nanoscale dimensions, because they are generated by interference between near fields. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5217-0 Authors Kazuo Tanaka, Department of Electronics and Computer Engineering, Gifu University, Yanagido 1-1, Gifu City, 501-1193 Japan Kiyofumi Katayama, Faculty of Administration and Informatics, University of Hamamatsu, Hamamatsu City, 431-2102 Japan Masahiro Tanaka, Department of Electronics and Computer Engineering, Gifu University, Yanagido 1-1, Gifu City, 501-1193 Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A new method for gain and noise figure enhancements in S-band thulium-doped fiber amplifier (TDFA) co-doped with aluminum is demonstrated using a macro-bending approach. The macro-bending suppresses both the amplified spontaneous emission (ASE) at 800 and 1,800 nm wavelength region and consequently improves the S-band gain of the TDFA. Gain enhancements between 5 and 8 dB are obtained with the macro-bending between 1,420 and 1,480 nm. The macro-bending also reduces the noise figure of the S-band TDFA. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-5216-1 Authors S. D. Emami, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia H. A. Abdul-Rashid, Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Malaysia S. Z. M. Yasin, Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Malaysia K. A. M. Shariff, Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Malaysia S. E. Mirnia, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia A. Parvizi, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia H. Ahmad, Photonics Research Center, University of Malaya, 50603 Kuala Lumpur, Malaysia S. W. Harun, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We report on a compact high-efficiency Cs slow atom beam source based on a retro-reflected two-dimensional magneto-optical trap (2D MOT). Employing two laser beams in an angled retro-reflected setup, we achieve 3D MOT loading rates greater than 8 × 10 9  atoms/s using only 20 mW of total laser power for the source. Content Type Journal Article Pages 1-4 DOI 10.1007/s00340-012-5220-5 Authors James R. Kellogg, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA Dennis Schlippert, Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany James M. Kohel, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA Robert J. Thompson, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA David C. Aveline, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA Nan Yu, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    We report experimental generation of a partially coherent Laguerre–Gaussian beam with mode orders 0 and l (i.e., LG 0 l beam) using a rotating ground-glass plate and a spatial light modulator. Focusing properties of the generated beam are studied both theoretically and experimentally. It is found that the focused intensity of the LG 0 l beam is shaped through varying the initial spatial coherence, and our experimental results agree well with the theoretical predictions. Our results will be useful in particle trapping and free-space optical communications. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5209-0 Authors Chengliang Zhao, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Yuan Dong, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Yuming Wang, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Fei Wang, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Yongtao Zhang, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Yangjian Cai, School of Physical Science and Technology, Soochow University, Suzhou, 215006 China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A new procedure with minimum sample preparation has been developed for a fast and serial analysis of cryolite with varying concentrations of dissolved alumina by liquid-phase laser ablation followed by Total Reflection X-Ray Fluorescence and induced coupled plasma optical emission spectroscopy. The analysis supplies the sodium/aluminium ratio of bath samples taken from industrial Hall-Herault reduction cells, as well as trace element relative concentrations. Two different types of molten samples taken directly from the aluminium production plant were placed under distilled de-ionized water in a quartz cell and subjected to pulsed laser ablation using the beam from a third harmonic Nd:YAG laser. Scanning electron microscopy examination shows the nanoparticles nature of the ablated material. The water-suspension is deposited on quartz reflectors for Total Reflection X-ray Fluorescence analysis or directly aspirated to the induced coupled plasma yielding the aluminium and sodium signals. Instrument quantification of the elements is performed by the use of aqueous standards. Validation tests were done with cryolite sample digestion and standard methods of sample quantification. The procedure can provide the aluminium/sodium ratio with adequate precision for aluminium production plant cell diagnostics and reveals the trace elements that could be considered as contamination. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-5175-6 Authors Ricardo Castell, Universidad Simon Bolivar, Apartado 89000, Caracas, 1080 Venezuela Eduardo D. Greaves, Universidad Simon Bolivar, Apartado 89000, Caracas, 1080 Venezuela Lyzeth Abdala, Universidad Simon Bolivar, Apartado 89000, Caracas, 1080 Venezuela Haydn Barros, Universidad Simon Bolivar, Apartado 89000, Caracas, 1080 Venezuela Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Analytical expressions for the components of the nonparaxial propagation a Lorentz-Gauss vortex beam in uniaxial crystals orthogonal to the optical axis are derived. The intensity and the phase distributions of the components of a Lorentz-Gauss vortex beam propagating in a uniaxial crystal orthogonal to the optical axis are shown by numerical examples. Even though one of the two transversal components of a Lorentz-Gauss vortex beam in the source plane is equal to zero, it emerges upon propagation inside the uniaxial crystal. Moreover, the beam profile of a Lorentz-Gauss vortex beam in the uniaxial crystal becomes twisted and tilted. The three components are completely different and have their respective evolution laws. The intensity distribution and the phase distribution of a Lorentz-Gauss vortex beam can be modulated by the uniaxial crystal, which is beneficial to the optical trapping and nonlinear optics involving in the special beam profile. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5118-2 Authors Yongzhou Ni, School of Sciences, Zhejiang A & F University, Lin’an, 311300 Zhejiang Province, China Guoquan Zhou, School of Sciences, Zhejiang A & F University, Lin’an, 311300 Zhejiang Province, China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Temporally resolved observation of microscopic structural dynamics of solids with ultrafast electron diffraction (UED) requires extremely short pulsed, highly charged, monoenergetic electron beams with sufficient transverse coherence length of several unit cells of the investigated samples. However, Coulomb repulsion defeats these parameters in free propagation of an electron pulse initially bright on the photo cathode. We demonstrate a new electron pulse compressor design based on a simple and compact RF structure incorporating a pair of gallium arsenide photoconductive semiconductor switches that are triggered by femtosecond laser pulses, thereby providing a longitudinal voltage gradient of up to 20 V/ps. Our proof of principle experiment achieved compression of bunches containing 26,000 electrons to a duration of below 750 fs and a beam diameter of 300 μm in the temporal and spatial focus of the device while maintaining the good beam collimation required for time resolved electron diffraction experiments. The simplicity of the compressor provides a strong incentive for its further development toward practical implementation in sub-relativistic UED experiments requiring the highest possible source brightness. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-012-5207-2 Authors G. H. Kassier, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa N. Erasmus, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa K. Haupt, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa I. Boshoff, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa R. Siegmund, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa S. M. M. Coelho, Department of Physics, University of Pretoria, Pretoria, 0002 South Africa H. Schwoerer, Physics Department, Laser Research Institute, Stellenbosch University, Stellenbosch, South Africa Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Isothermal magnetization data in the critical region of the ferromagnetic transition for Co-doped SnO 2 -based diluted magnetic semiconductor were measured and analyzed in terms of the modified Arrott plot method and, independently by the Kouvel–Fisher method. The critical exponents β , γ , and δ , corresponding to spontaneous magnetization, initial susceptibility and isothermal magnetization, respectively, were determined and the values are found to be comparable to the mean-field model. The critical exponent values are found to be consistent with the Widom scaling relation and the universal scaling hypothesis. The temperature variation of the effective critical exponent is found to show the characteristic behavior of a disordered system. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s10948-012-1697-8 Authors Sunita Mohanty, Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039 India S. Ravi, Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039 India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Multiferroic BiFeO 3 and Cr-doped (0.90)BiFe 1− x Cr x O 3 –(0.10)BaTiO 3 ( x =0.00, 0.03, and 0.05) nanocomposites were prepared by sol–gel method. Optimum calcination and sintering strategies for obtaining pure perovskite phase have been determined. X-ray diffraction and transmission electron microscope (TEM) were used for the structural and particle size analysis, whereas LCR and SQUID magnetometer was used for dielectric and magnetic measurements. TEM measurements show that the average particle sizes of all the samples were ∼19 nm. The dielectric constant was found to be increased twofold in low frequency region with the Cr-doping for x =0.05 in (0.90)BiFe 1− x Cr x O 3 –(0.10)BaTiO 3 . The hysteresis curve ( M – H ) exhibits ferromagnetic nature for all the samples ( x =0.0, 0.03, and 0.05) and the spontaneous magnetization at room temperature was found to be 0.63 emu/gm in pure BiFeO 3 , which increased to 0.99 emu/gm for x =0.05. Zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves show large discrepancy suggesting spin glass behavior. Content Type Journal Article Category Original Paper Pages 1-6 DOI 10.1007/s10948-012-1736-5 Authors Mohit Sahni, Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, India Sushant Singh, Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, India Richa Bhargava, Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, India Amit Kumar Chawla, Institute Instrumentation Centre, IIT Roorkee, Roorkee, India Ramesh Chandra, Institute Instrumentation Centre, IIT Roorkee, Roorkee, India Anshuman Dalvi, Department of Physics, BITS, Pilani, India Neha Gupta, Department of Physics, BITS, Pilani, India Sanjeev Kumar, Dharmsinh Desai University, Gujarat, India Naresh Kumar, Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    Temperature-dependent magnetic flux density ( B ) data, clearly exhibiting a transition temperature called intrinsic blocking temperature for some metallic samples in zero field cooled-warmed (ZFC-W) curves without employing an external magnetic field, has been obtained by a simple method. The reasons of the increase and decrease in the measured B -field at low temperature in zero magnetic-field were discussed. Co, CoPt 3 and Co/Au, CoPt 3 /Au core-shell nanoparticles, prepared by the reverse-micelle microemulsion method, were used as test materials. The blocking temperature was measured at a cusp of the measured magnetic field, B (produced by the sample), versus the temperature curve during warming up of the sample from a very low temperature (≤15 K) to room temperature. All the samples showed a blocking temperature at 45, 50, 40, and 42 K, respectively, for Co, CoPt 3 , Co/Au, and CoPt 3 /Au nanoparticles. A completely intrinsic behavior of the sample’s magnetic moment was revealed by our method since no applied external field was used, yielding a truly spontaneous magnetization behavior. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s10948-012-1742-7 Authors Ghazaleh Bahmanrokh, Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Mansor Hashim, Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Ismayadi Ismail, Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Nayereh Soltani, Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Parisa Vaziri, Department of Medical Physics and Biomedical Engineering, Shahid Beheshti University of Medical Sciences, Velenjak, Daneshju Blvd., Tehran, 1983963113 Iran Mohd Shamsul Ezzad Shafie, Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Manizheh Navaseri, Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    A systematic investigation was done to determine the structural, morphological and magnetic properties of Zn 0.8 Co 0.2 O nanoparticles synthesized by a simple autocombustion technique. XRD, FE-SEM and EDX measurements were implemented for the structural, morphological and compositional investigation of the product. Additionally VSM was used for the magnetic property investigations of the sample. The average particle size of the nanoparticles was estimated using Debye–Scherrer’s equation and found to be 20.8 nm. Magnetization measurements have shown that the particles have room-temperature ferromagnetic behavior with relatively high coercive fields. Magnetization and the coercive field of the sample increase by decreasing the temperature, as expected. FMR signal confirms the room-temperature enhanced ferromagnetic behavior without Co precipitates. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1772-1 Authors Yüksel Köseoğlu, Department of Physics, Fatih University, Buyukcekmece, 34500 Istanbul, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    We have examined theoretically the electronic band structure and Fermi surface (FS) of the tetragonal low-temperature superconductor Bi 2 Pd. Our main results are that (i) the Pd 4 d and Bi 6 p states determine the main peculiarities of the multiple-sheet FS topology, thus for this material a complicated superconducting gap structure with different energy gaps on different FS sheets should be assumed; (ii) the effect of spin-orbit coupling is of minor importance for the distributions of the near-Fermi electronic states; and (iii) this phase adopts a 3D-like type owing to directional bonds between the adjacent atomic sheets. Content Type Journal Article Category Letter Pages 1-4 DOI 10.1007/s10948-012-1776-x Authors I. R. Shein, Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg, Russia A. L. Ivanovskii, Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg, Russia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    The effect of electrolyte pH on structural, magnetic, and magnetoresistive properties of Co–Ni films was studied. The films were deposited on a titanium substrate from the electrolytes with 4.10±0.05, 3.14±0.05, and 2.14±0.05 pH values. The Co–Ni system exhibited anomalous codeposition. Structural analysis indicated that the films had (220) preferential oriented face-centered cubic structure and their surface became smoother as the electrolyte pH decreased. The compositional and magnetic analysis revealed that an increase of the Co content in the films resulted in an increase in saturation magnetization and coercivity. Magnetoresistance curves indicated that the films show anisotropic magnetoresistance. Longitudinal and transversal magnetoresistances were found to be the highest values of 8 % and 7 %, respectively, for the film deposited at a low electrolyte pH. The variation of the Co:Ni ratio in deposits caused by the change of the electrolyte pH has a considerable effect on the properties of the films. Content Type Journal Article Category Original Paper Pages 1-5 DOI 10.1007/s10948-012-1774-z Authors Ali Karpuz, Physics Department, Kamil Ozdag Science Faculty, Karamanoglu Mehmetbey University, Karaman, Turkey Hakan Kockar, Physics Department, Science & Literature Faculty, Balikesir University, Balikesir, Turkey Mursel Alper, Physics Department, Science & Literature Faculty, Uludag University, Bursa, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    We theoretically investigated the generation of quantum-correlated photon pair through spontaneous four-wave mixing in tellurite microstructured optical fiber (MOF). We evaluated the performance of photon pair generation in tellurite fibers based on Raman gain coefficient spectra. It was shown that the TBSN16P6W tellurite fiber provided a low Raman noise on correlation photon generation over a wide pump-idler detuning range. We can choose proper tellurite composition to obtain a low Raman gain window over wide range for correlated photon pair generation. We also designed the tellurite MOF structure to obtain a small dispersion value with high nonlinear coefficient at telecommunication wavelengths, thus realize efficient quantum-correlated photon pair generation. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5200-9 Authors Xin Yan, Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Nagoya, Tempaku 468-8511, Japan Meisong Liao, Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Nagoya, Tempaku 468-8511, Japan Tong Hoang Tuan, Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Nagoya, Tempaku 468-8511, Japan Takenobu Suzuki, Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Nagoya, Tempaku 468-8511, Japan Yasutake Ohishi, Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Nagoya, Tempaku 468-8511, Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    An analytical expression of an Airy beam passing through a fractional Fourier transform (FRFT) system is presented. The effective beam size of the Airy beam in the FRFT plane is also derived. The influences of the order of FRFT, the modulation parameter, and the transverse scale on the normalized intensity distribution and the effective beam size of an Airy beam in the FRFT plane are examined. The order of FRFT controls the effective beam size and the orientation of the beam spot. The modulation parameter affects the effective beam size and the number of lateral side lobes. The normalized intensity distribution and the effective beam size are both proportional to the transverse scale. Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5117-3 Authors Guoquan Zhou, School of Sciences, Zhejiang A and F University, Lin’an, Hangzhou, 311300 Zhejiang Province, China Ruipin Chen, School of Sciences, Zhejiang A and F University, Lin’an, Hangzhou, 311300 Zhejiang Province, China Xiuxiang Chu, School of Sciences, Zhejiang A and F University, Lin’an, Hangzhou, 311300 Zhejiang Province, China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    This study addresses the initiation of laser-induced breakdown of dielectric materials in the nanosecond regime under multi-wavelength conditions. In particular, the competition between multi-photon absorption and electronic avalanche as ionization mechanisms in KDP crystal is studied. Since they are both dependent on the laser frequency and intensity of incident radiations, we carried out two experiments: in mono-wavelength configuration at 1,064 nm and in multi-wavelengths configuration applying the simultaneous mixing of 1,064 and 355 nm radiations with various fluence ratios. To interpret experimental data, a model based on heat transfer and which includes ionization processes has been developed for both configurations. The comparison between experiments and modeling results first indicates that avalanche can be responsible for optical breakdown at 1,064 nm. Then, the study underlines the existence of a coupling effect in the multi-wavelength configuration where multi-photon absorption and electronic avalanche both contribute to the breakdown. From a general point of view, the model accounts for the experimental trends and particularly reveals that the electronic recombination timescale may have an important role in the scenario of nanosecond laser-induced breakdown. Content Type Journal Article Pages 1-12 DOI 10.1007/s00340-012-5238-8 Authors S. Reyné, CEA-Cesta, 15 Avenue des Sablières, 33114 Le Barp, France G. Duchateau, CELIA, UMR-5107 Université Bordeaux I-CNRS-CEA, 351 Cours de la libération, 33405 Talence, France J. Y. Natoli, Institut Fresnel, UMR-CNRS 6133, D.U. St Jérôme, 13397 Marseille, France L. Lamaignère, CEA-Cesta, 15 Avenue des Sablières, 33114 Le Barp, France Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    In this work, we demonstrate for the first time that it is possible to transfer simultaneously an ultra-stable optical frequency and precise and accurate timing over 540 km using a public telecommunication optical fiber network with Internet data. The optical phase is used to carry both the frequency information and the timestamps by modulating a very narrow optical carrier at 1.55 μm with spread spectrum signals using two-way satellite time transfer modems. The results in terms of absolute time accuracy (250 ps) and long-term timing stability (20 ps) well outperform the conventional Global Navigation Satellite System or geostationary transfer methods. Content Type Journal Article Category Rapid Communication Pages 1-4 DOI 10.1007/s00340-012-5241-0 Authors Olivier Lopez, Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris Cité, CNRS, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France Amale Kanj, LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 Av. de l’Observatoire, 75014 Paris, France Paul-Eric Pottie, LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 Av. de l’Observatoire, 75014 Paris, France Daniele Rovera, LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 Av. de l’Observatoire, 75014 Paris, France Joseph Achkar, LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 Av. de l’Observatoire, 75014 Paris, France Christian Chardonnet, Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris Cité, CNRS, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France Anne Amy-Klein, Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris Cité, CNRS, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France Giorgio Santarelli, LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 Av. de l’Observatoire, 75014 Paris, France Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Quartz-enhanced photoacoustic spectroscopy (QEPAS) is demonstrated for acetylene detection at atmospheric pressure and room temperature with a fiber-coupled distributed feedback (DFB) diode laser operating at ~1.53 μm. An efficient approach for gas concentration calibration is demonstrated. The effect of residual amplitude modulation on the performance of wavelength modulated QEPAS is investigated theoretically and experimentally. With optimized spectrophone parameters and modulation depth, a minimum detectable limit (1 σ ) of ~2 part-per-million volume (ppmv) was achieved with an 8.44-mW diode laser, which corresponds to a normalized noise equivalent coefficient (1 σ ) of 6.16 × 10 −8  cm −1  W/Hz 1/2 . Content Type Journal Article Pages 1-8 DOI 10.1007/s00340-012-5221-4 Authors Y. Cao, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China W. Jin, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China H. L. Ho, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China L. Qi, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China Y. H. Yang, Department of Opto-electronics Engineering, School of Instrument Science and Opto-electronics Engineering, BeiHang University, Beijing, 100191 China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    Based on a tight-binding model and a generalized Green’s function method in the Landauer−Büttiker formalism, the current-voltage characteristics, the noise power resulting of the spin-dependent current fluctuations and Fano factor of poly(G)-poly(C) DNA molecule sandwiched between ferromagnetic three-dimensional electrodes (FM/DNA/FM) are numerically investigated. It is found when the bias voltage increased, the current and noise power increase and the Fano factor decreases. Our results show the spin-dependent transport properties are significantly influenced by the electrode/molecule coupling strength so that the reinforcement of the electrode/molecule coupling strength give rise to increasing of the current and noise power so that the Fano factor decreased. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s10948-012-1768-x Authors A. Ahmadi Fouladi, Department of Physics, Sari Branch, Islamic Azad University, Sari, Iran S. A. Ketabi, School of Physics, Damghan University, Damghan, Iran Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Beschreibung:    We have investigated the spectral dispersion of second molecular hyperpolarizability γ (− ω ′; ω , − ω , ω ) of three derivatives of heteroarylene methine by antiresonant ring interferometric nonlinear spectroscopic technique using femtosecond modelocked Ti:sapphire laser in the spectral range of 725–820 nm. The observed dispersion of γ has been explained in the framework of three-essential states model involving the ground state, a one-photon excited state and a two-photon excited state. The spectral response of the hyperpolarizability has been correlated with the electronic and chemical structures of the three derivatives of heteroarylene methine. The estimated γ values have been compared to the fundamental quantum mechanical limit. We have found for the first time that the heteroarylene methines approach this limit within a factor of 2 while even the best known molecule so far falls short of this limit by a factor of 30. Content Type Journal Article Pages 1-9 DOI 10.1007/s00340-012-5199-y Authors B. Bhushan, Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076 India S. K. Kumar, Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076 India S. S. Talwar, Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076 India T. Kundu, Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076 India B. P. Singh, Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076 India Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    N-ZnO/Ga 2 O 3 / p -GaN heterojunction light-emitting diode (LED) was fabricated by metal-organic chemical vapor deposition. Compared with the n -ZnO/ p -GaN structure, the deep level visible emission at 525 nm was completely suppressed while UV emission at ~392 nm was significantly improved in ZnO/Ga 2 O 3 / p -GaN structure. The role of Ga 2 O 3 in n -ZnO/Ga 2 O 3 / p -GaN heterojunction LED was discussed in detail. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5219-y Authors Yuanda Liu, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Hongwei Liang, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Xiaochuan Xia, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Rensheng Shen, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Yang Liu, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Jiming Bian, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Guotong Du, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 China Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    According to the recent calculations, more efficient THz pulse generation is possible using relief grating on the front surface of the generating LiNbO 3 (LN) crystal for tilted-pulse-front-excitation rather than imaging the pump spot on a reflection grating into the LN crystal. Very recently, it was shown that—compared to a free-standing LN surface-relief grating—significantly higher diffraction efficiency can be reached if the grating profiles are filled with fused silica. Since realisation of such a setup is technically very challenging, in the present paper, we analyse the case where the input side of the LN grating is immersed into a refractive index matching liquid (RIML) instead of a solid material. Our results showed that the diffraction efficiency remains above 90 % for a refractive index ranging 1.45–1.60 of the applied RIML, and it is as high as 99 % for using the RIML for BK7. For this case, we carried out detailed calculations for various grating parameters. We propose a practical setup applying tilted input and slightly tilted output surfaces resulting in low losses and high diffraction efficiency for the pump. We conclude that a contact grating setup using BK7 RIML is suitable for producing THz pulses even in the mJ-energy range. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5201-8 Authors Zoltán Ollmann, Institute of Physics, University of Pécs, Ifjúság ú. 6, 7624 Pécs, Hungary János Hebling, Institute of Physics, University of Pécs, Ifjúság ú. 6, 7624 Pécs, Hungary Gábor Almási, Institute of Physics, University of Pécs, Ifjúság ú. 6, 7624 Pécs, Hungary Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    The present study develops and investigates for the first time a unique spatial continuously tunable cone laser based on a dye-doped cholesteric liquid crystal (DDCLC) film with an LC-birefringence (Δ n ) gradient. A continuous Δ n variation can be generated in a cell by diffusion and self-organization of CLC after four DDCLC mixtures with a discrete variation of Δ n are successively injected into an empty cell. Not only the CLC photonic structure but also the lasing wavelength and the cone angle of the obtained conically symmetric emitted lasing ring can be tuned continuously by continuously changing the pumped position of the cell with an Δ n gradient. The continuous tunabilities in the lasing wavelength and the corresponding emitted cone angle of the lasing ring are 605.8 → 568.1 nm and 29° → 50°, respectively, within a spatial interval of about 33 mm in the cell. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5218-z Authors Chia-Rong Lee, Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, 701 Taiwan Shih-Hung Lin, Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, 701 Taiwan Jia-De Lin, Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, 701 Taiwan Ting-Shan Mo, Department of Electronic Engineering, Kun Shan University of Technology, Tainan, 710 Taiwan Chie-Tong Kuo, Department of Physics and Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Kaohsiung, 804 Taiwan Shuan-Yu Huang, School of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A laser-plasma source comprising a rotating cryogenic solid-state Xe target has been studied for use in extreme ultraviolet lithography (EUVL) systems equipped with La/B 4 C mirrors. The laser-to-EUV power conversion efficiency (CE) of the cryogenic Xe target was improved to achieve a maximum CE of 0.15 % at 6.7 nm with 0.6 % bandwidth. We successfully demonstrated the continuous generation of EUV light with an average power of 80 mW at 6.7 nm with 0.6 % bandwidth using a Nd:YAG slab laser at a repetition rate of 320 Hz and an average power of 100 W. Scaling-up of the laser-plasma source for use as a future EUVL source is also discussed. Content Type Journal Article Pages 1-5 DOI 10.1007/s00340-012-5215-2 Authors Sho Amano, Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Ako-gun, Hyogo 678-1205, Japan Tomoaki Inoue, Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Ako-gun, Hyogo 678-1205, Japan Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    The frequency upconversion (UC) emission throughout the visible region from the Y 2 O 3 :Ho 3+ –Tm 3+ –Yb 3+ co-doped phosphors synthesized by using low temperature combustion process upon excitation with a diode laser operating at 980 nm have been presented. The colour emission tunability in co-doped phosphor has been observed on increasing the pump power and seen by the naked eyes. The tunability in colour emission has also been visualized by CIE chromaticity diagram. The variation in UC emission intensity of the 1 G 4  →  3 H 6 (Tm 3+ ) and 5 F 3  →  5 I 8 (Ho 3+ ) transitions lying in the blue region has been monitored with increase in the pump power and marked that their ratio can be used to determine the temperature. The developed phosphor has been used to record fingerprints. The observed most intense visible colour emission from the developed material may be used for photodynamic therapy and as an alternative of traditional fluorescent biolabels. Content Type Journal Article Pages 1-6 DOI 10.1007/s00340-012-5224-1 Authors Anurag Pandey, Laser and Spectroscopy Laboratory, Department of Applied Physics, Indian School of Mines, Dhanbad, 826004 Jharkhand, India Vineet Kumar Rai, Laser and Spectroscopy Laboratory, Department of Applied Physics, Indian School of Mines, Dhanbad, 826004 Jharkhand, India Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    In this paper, we discuss the interest of the singular value decomposition (SVD) data processing method applied to the in situ monitoring of gases (N 2 O) b mid-infrared quantum cascade laser absorption spectroscopy. An approach by simulation is used to determine the most appropriate parameters of the SVD treatment for this specific laser sensing application. The simulation is further used to estimate the effectiveness of the SVD in terms of improvement of the concentration data precision. Finally, the proposed SVD method is applied to experimental N 2 O measurements achieved in the laboratory with calibrated gas samples and with N 2 O flux measurements yielded during a field campaign in farm parcels. Content Type Journal Article Pages 1-11 DOI 10.1007/s00340-012-5205-4 Authors Irène Mappe-Fogaing, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Lilian Joly, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Georges Durry, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Nicolas Dumelié, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Thomas Decarpenterie, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Julien Cousin, Groupe de Spectrométrie Moléculaire et Atmosphérique, Unité Mixte de Recherche Du Centre National de la Recherche Scientifique (UMR CNRS 6089), UFR Sciences Exactes et Naturelles, Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    A novel model of ultrafast interaction between THz pulse and carriers is built to study the THz-wave-induced quenching of femtosecond-laser-excited photoluminescence in CdTe and GaAs. Photoluminescence quenching is due to the nonequilibrium intervalley phonons induced by the THz field and subsequent decrease of the recombination efficiency of the electron–hole pairs. And the PLQ versus laser intensity experimental result agrees with the analysis. Content Type Journal Article Pages 1-7 DOI 10.1007/s00340-012-5191-6 Authors Zheng Chu, Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 China Jinsong Liu, Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 China Jingle Liu, Department of Physics, Applied Physics and Astronomy, Center for Terahertz Research, Rensselaer Polytechnic Institute, Troy, NY 12180, USA Journal Applied Physics B: Lasers and Optics Online ISSN 1432-0649 Print ISSN 0946-2171

Beschreibung:    The present study is focused on the copper-doped ZnO system. Bulk copper-doped ZnO pellets were synthesized by a solid-state reaction technique and used as target material in pulsed laser deposition. Thin films were grown for different Cu doped pellets on sapphire substrates in vacuum (5×10 −5  mbar). Thin films having (002) plane of ZnO showed different oxidation states of dopants. M – H curves exhibited weak ferromagnetic signal for 1–3 % Cu doping but for 5 % Cu doped thin film sample showed the diamagnetic behavior. For deeper information, thin films were grown for 5 % Cu doped ZnO bulk pellet in different oxygen ambient pressures and analyzed. PL measurement at low temperature showed the emission peak in thin films samples due to acceptor-related transitions. XPS results show that copper exists in Cu 2+ and Cu +1 valence states in thin films and with increasing O 2 ambient pressure the valence-band maximum in films shifts towards higher binding energy. Furthermore, in lower oxygen ambient pressure (1×10 −2  mbar) thin films showed magnetic behavior but this vanished for the film grown at higher ambient pressures of oxygen (6×10 −2  mbar), which hints towards the decrease in donor defects. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s10948-012-1710-2 Authors S. Karamat, Natural Science and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637616 Singapore R. S. Rawat, Natural Science and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637616 Singapore T. L. Tan, Natural Science and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637616 Singapore P. Lee, Natural Science and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637616 Singapore S. V. Springham, Natural Science and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637616 Singapore Anis-ur-Rehman, Department of Physics, COMSATS Institute of Information Technology, 22060 Islamabad, Pakistan R. Chen, Division of Physics and Applied Physics, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore H. D. Sun, Division of Physics and Applied Physics, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939