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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 101-114 
    ISSN: 1432-0649
    Schlagwort(e): 42.40 ; 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We describe the principles of holographic storage and reconstruction of ultrashort light pulses using spectrally nonselective media. This can be achieved by the application of a 3-D recording medium and by the holography of waves produced by spatial spectral decomposition of light pulses. We also describe various transformations of optical temporal signals based on holographic spectral filtering and nonlinear interaction of spectral decomposition waves.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 49-51 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have developed a new technique for efficient suppression of the nonresonant background in coherent anti-Stokes Raman scattering (CARS). The advantage of this technique, which is based upon phase-controlled superposition of an appropriately selected reference signal, is presented in theory and demonstrated experimentally by the example of the S(3) (pure rotational) transition of molecular hydrogen.
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 61-62 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract N2-temperature measurements have been performed by coherent anti-stokes Raman scattering (CARS) up to more than 3200 K using a commercial heated graphite tube furnace. Surface radiation pyrometry served as the reference technique yielding good agreement between pyrometric and CARS-based temperature determination, resulting in an overall temperature uncertainty of ±80 K for a spectrum obtained at 1 bar and 3230 K.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 541-545 
    ISSN: 1432-0649
    Schlagwort(e): 06.607 ; 42.60 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Amplified spontaneous emission of a dye cell is parametrically amplified in barium betaborate (BBO) crystals. Pumping the system by the third harmonic of a Nd:YAG laser a tuning range from 3500 to 25080 cm−1 is accessible with energy conversion efficiencies of several percent. Properties of ultrashort light pulses in the visible and UV spectral range are presented. A spectral width of 10 cm−1 and a pulse duration of approximately 20 ps are measured.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 303-306 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Parametric amplification was shown to take place in the response of an ensemble of nonlinear classical oscillators upon the interaction with a second pulse.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-0649
    Schlagwort(e): 52.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Coherent anti-Stokes Raman Spectroscopy (CARS) is applied to a filamentary discharge in H2. Temperature and density profiles of molecular hydrogen are determined. The maximum temperature observed on the discharge axis is 5685 K. Vibrational and rotational transitions are analyzed and a difference in the evaluated temperatures is found which increases with pressure. In addition, the reactive thermal conductivity associated with dissociation is determined and compared with earlier work.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 386-394 
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A rich emission spectrum in the wavelength range 300–600 nm, including 50 spectral lines, has been observed as a pulsed dye laser is tuned to the 42 S 1/2–32 D 5/2 two-photon resonance in potassium vapor. It is found that many kinds of mechanisms, including energy pooling, harmonic generation, quadrupole radiation, excitation transfer, and multiwave mixing etc., are involved in producing these lines. The process for each spectral line has been identified and is presented in tabular form.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 81.40 ; 78.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We first discuss theoretically the enhancement of the optical nonlinearity due to quantum confinement in semiconductor-doped glasses. This quantum confinement mediated enhancement also pertains to the figure of merit x (3)/α, in which case it is due to a decrease in the spectral width rather than in an increase of the matrix elements. We then report on frequency and size-dependent measurements which confirm the theoretically expected enhancement due to quantum confinement.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 55-62 
    ISSN: 1432-0649
    Schlagwort(e): 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The optical properties of the nonlinear crystals lithium borate (LBO), barium borate (BBO) and deuterated potassium phosphate (KD*P) are compared for second and third harmonic generation of Nd:YAG laser radiation. In an experimental investigation the conversion efficiency has been measured as a function of the energy density of 8 ns long laser pulses, generated by a commercial Nd:YAG oscillator-amplifier system. In LBO and BBO the second harmonic generation saturates at an energy density of about 1.5 J cm−2 at efficiencies of 55–60%. In KD*P comparable efficiencies (40–55%) require energy densities of 2–2.6 J cm−2. Similar results are obtained for frequency tripling. In LBO and BBO saturated efficiencies of 20–25% are measured at an energy density of about 1.5 J cm−2. In KD*P efficiencies of 20% are obtained at energy densities exceeding 2 J cm−2. Besides for doubling and tripling of Nd:YAG laser radiation the phase-matching is calculated for frequency conversion of tunable laser light. The results demonstrate that in LBO and BBO phase-matched sum-frequency mixing of UV and infrared laser light generates tunable radiation at wavelengths as short as the transmission cut-off at 160 nm and 190 nm, respectively.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 84-89 
    ISSN: 1432-0649
    Schlagwort(e): 36.40 ; 42.65 ; 47.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Coherent Stokes and anti-Stokes Raman scattering CSRS and CARS have been employed to study the spectroscopy of nitrogen molecules and clusters in the expansion of a supersonic jet. In the vibrational spectrum, at strong stagnation conditions, an intense redshifted peak is observed which can be assigned to the intramolecular vibrations in large N2 clusters having adopted the β-phase structure. Another weak feature is assigned to nitrogen clusters in the α-phase. In the rotational region of the spectrum only monomer features have been observed. The failing to observe librational motions is consistent with the finding that the nitrogen clusters are predominantly in the orientationally unordered β-phase. The low rotational temperature suggests supercooling of the β-phase.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 96-101 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.55
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We analyze a nonlinear mirror based on Raman interactions. The mirror is a combination of a Raman-active medium and a tetrachroic mirror. The reflections of the nonlinear mirror at two input frequencies differing by the Raman shift are calculated and its properties and possible applications are discussed.
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 150-153 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract It is shown theoretically that the semilinear phase conjugate mirror exhibits bistability when it is “seeded” by a weak external pump beam. Full hysteresis in the output intensity is obtained when the “seed” intensity is swept through the two-stable-states region and the coupling strength is below the self-oscillation threshold.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 158-162 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.55
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A nonlinear mirror is used to provide a passive negative feedback in an actively mode-locked pulsed Nd:YAG laser. Trains of 250 ps pulses with a total length of up to 50 microseconds were generated. The train duration is limited only by the flashlamp pump pulse length.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 211-216 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 51.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract When a two-color laser beam is introduced into pressurized hydrogen, about 40 laser emission lines are generated from the ultraviolet to the visible regions. This phenomenon is ascribed to the stimulated Raman effect due to a combination ofJ=1 →J=3 rotational andv=0 →v=1 vibrational transitions. By introducing the two-color laser beam, the threshold for generation of the rotational line is substantially reduced. The present phenomenon is attributed to four-wave mixing, which allows efficient generation of higher-order rotational and vibrational Raman lines.
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  • 15
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract It is shown that for waves incident with a polarisation in the plane of the grating the component of the electric field in the direction of propagation must be included in the calculations. Coupled differential equations for both the transverse and longitudinal components are derived for wave interaction in photorefractive BaTiO3. Analytic solutions for the electric field of the signal wave are obtained under the assumption that the pump wave is undepleted. For the parameters considered the longitudinal component is shown to be negligible.
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  • 16
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We represent an ultrafast beam-deflection method as a simple and powerful tool for the time-resolved measurement of induced changes of the refractive index in the order of Δn=10−5. The method is applied for measuring the changes of components of the refractive index parallel and perpendicular to the pump-pulse polarization on a femtosecond time scale. Fused silica and CS2 are used as samples for demonstrating our method.
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  • 17
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The phase-matched direct tripling of picosecond light pulses of a mode-locked Nd: glass laser in a new cyanine dye PMC is studied. The solvents trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) are applied. The S 0–S 1 absorption peak of the dye is around λ=480 nm and the absorption cross section at the third-harmonic wavelength of λ3=351.3 nm is only σ3≈1×10−19 cm2. Phase-matching occurred at concentrations of CPM=0.0874 mol/dm3 in HFIP and 0.1088 mol/dm3 in TFE. A third-harmonic energy conversion efficiency of ηE≈0.01 was achieved at a pump-laser peak intensity of I 0L≈2.5×1011 W/cm2 in a 5 mm long sample of PMC in TFE. The conversion efficiency is limited by destruction of phase-matching due to the intensity-dependent nonlinear refractive index of the dye solutions.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 57 (1993), S. 431-434 
    ISSN: 1432-0649
    Schlagwort(e): 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Nd:YAG and a Nd:YAG-pumped dye laser are used to generate tunable deep ultraviolet radiation down to 240 nm in a lithium triborate crystal (LBO) by noncollinear sum-frequency mixing. All longer wavelengths can be generated by a combination of harmonic generation of the dye laser and sum-frequency mixing, 240 nm being the near noncritical limit. A set of versatile Sellmeier dispersion equations is derived to satisfactorily predict phase-matching in LBO.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 53 (1991), S. 153-159 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We consider the coupling between two photorefractive unidirectional ring resonators. The first resonator is driven by an external laser beam via photorefractive two-wave mixing. The internal oscillating beam is then employed to drive the second ring resonator via the same mechanism. Closed form solutions for the oscillation intensities and frequencies are given, and their numerical results are presented and discussed.
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  • 20
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The theoretical description of parametric cascaded processes produced by intersecting beams in crystals with second-order susceptibility is presented. A common system of equations in the Slowly Varying Amplitude (SVA) approximation is used to treat the phenomenon. This approach provides a description of overall self-diffraction processes and the equations are well suited for numerical simulations. A relation between phase-matching conditions for parametric cascading processes and diffraction efficiency is found. Pump depletion influence is analysed. The results of numerical simulations are in good agreement with experimental data.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 121-124 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The formation of two-Dimensional (2D) odd dark spatial solutions is analyzed numerically at an initial helical dark-beam phase distribution. Experimental results are presented for the first time confirming the existence of two-dimensional optical even dark solitons (ring dark solitons). Several aspects of the evolution of input 1D and 2D odd/even dark beams are compared qualitatively.
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  • 22
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We present the theory of electrostrictional interaction of soliton pulses in optical fibers. Solitons excite acoustic waves propagating in the direction transverse to the fiber axis. Scattering of optical radiation on these waves leads to a timing jitter of the optical pulses arrival time. We consider this effect as nonlinear self-scattering of light on acoustic waves. Because of the fact that a value of acoustic lifetime can reach a value of about 100 ns self-scattering on acoustic waves can be observed for a single optical pulse as well as for an optical pulse sequence as a whole. The value of single soliton self-frequency shift due to excitation of acoustic waves as a function of soliton duration have been obtained. For soliton duration τsol 〉 14 ps an acoustic wave soliton self-frequency shift is larger than the Raman soliton self-frequency shift. The obtained theoretical results describe well the long-range interaction of soliton pulse trains in an optical fiber. The value of bit error rate due to electrostrictional interaction of optical pulses in high bit rate, ultra long soliton communication systems have been obtained.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 489-491 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 63.20 ; 78.30
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Generation of infrared radiation in ts-infrared transmission window (6.8–7.7 µm) is reported for the first time by non-collinear difference-frequency mixing of the Nd: YAG second harmonic and the same-pumped dye (Rh-610) laser radiation in a lithium-iodate crystal. The spectrum of polythene sheets was run with the generated radiation.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 62 (1996), S. 309-311 
    ISSN: 1432-0649
    Schlagwort(e): 52.40 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The effects of the development of the three-wave phase on the amplitude of the pumping laser light, the scattered light, and the electron plasma wave are studied. Analytical solutions are obtained to describe a pumping laser light decreasing with time and the development of the electron plasma wave and scattered wave from an initial increasing state to saturation and finally to a decaying state which is closely related to the three-wave phase.
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  • 25
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report on an experimental and numerical investigation of the process of spontaneous optical vortices nucleation in a wave front of a laser beam passed through a photorefractive LiNbO3 : Fe crystal with self-induced nonlinear lens. The complex lens structure produces mainly defocusing of the beam passing through the crystal due to a negative variation of the refractive index, whereas side parts of the lens have a positive sign of refractive-index variation and partially focus the beam. The resulting wave-front distortions lead to a phase bifurcation occurring at a certain distance after the crystal when the amplitude of the light wave becomes zero. We study in detail the process of edge dislocation nucleation and its decay in the near field producing a pair of unity-charged opposite-sign screw dislocations. After birth, they spread along dislocation axes as stable objects.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 55 (1992), S. 117-120 
    ISSN: 1432-0649
    Schlagwort(e): 42.55 ; 42.65 ; 02
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The usual way of obtaining rate equations (RE) and a single equation for the field amplitude (EFA) from the semiclassical laser equations (Lorenz-Haken model) is reexamined by undertaking a systematic elimination procedure developed in synergetics. The RE and EFA are justified in the case 1 (γ⊥≫γ∥, κ) and case 2 (γ⊥, γ∥≫κ), respectively. We show that, because the eliminated variable happens to contain a considerable contribution from an unstable mode, the usual elimination technique in the case 3 (γ⊥, κγ∥) leads to an inconsistency. As important by-products we obtain the RE and EFA for arbitrary cavity relaxation constant (κ). Some remarks are given on the direct elimination technique in the non-diagonal representation in the study of instabilities.
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  • 27
    ISSN: 1432-0649
    Schlagwort(e): 42.55.M ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Spectral broadening of stimulated Raman scattering has been studied in a phenylethanol liquid-core wave-guide optical fiber by using a frequency-doubled Q-switched Nd: YAG laser. Four orders of Stokes lines were observed. All the Stokes lines were asymmetrically broadened favoring the lower frequencies. Both the red-shifted broadening and the blue-shifted broadening increased with the rise of the temperature of the Raman medium. The asymmetric broadening was discussed to be mainly due to the effect of the cascaded stimulated Rayleigh-wing scattering.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 55 (1992), S. 311-318 
    ISSN: 1432-0649
    Schlagwort(e): 78.30 ; 78.32 ; 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The stimulated Raman scattering (SRS) and four-wave mixing (FWM) processes have been studied in detail in CH4 gas pumped by the third-harmonic of Nd:YAG laser at γ=355 nm. The conversion efficiency and average output energy have been measured for the various Stokes and anti-Stokes lines at different experimental conditions. The threshold input energy at various CH4 pressures has been calculated for the unguided and capillary waveguide Raman cells. The calculated values for the capillary case have been compared with the measured values at different CH4 pressures and the two results are in good agreement.
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  • 29
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract An optical parametric oscillator (OPO), as a novel kind of broadband Stokes source, is employed for coherent anti-Stokes Raman spectroscopy (CARS). Compared to the conventional dye laser configuration OPO-CARS offers practical advantages. The tunable OPO allows a fast and comfortable frequency tuning. The excitation bandwidth of about 35 cm−1 (FWHM) limits the spectral range of effective and stable single pulse CARS generation but can be used to enhance selected spectral structures.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 55 (1992), S. 388-390 
    ISSN: 1432-0649
    Schlagwort(e): 33.00 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract O2 temperature measurements at T=1910K have been performed by coherent anti-Stokes Raman scattering (CARS) inside a homogeneously heated gas volume of a tube furnace. The oxygen CARS spectrum can now be modeled accurately within the higher vibrational levels of the Q-branch manifold populated at flame temperatures using recently available spectroscopic data and collisional broadening coefficients.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 55 (1992), S. 381-387 
    ISSN: 1432-0649
    Schlagwort(e): 33.00 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Four wavelength extensions have been investigated by stimulated Raman scattering in hydrogen or deuterium gas of the 248 nm fundamental output of a narrow-band tunable KrF excimer laser. They have been used to acquire laser-induced fluorescence spectra of NO and OH in flames at atmospheric pressure. NO is detected in relatively high rotational states within the γ-band electronic system at 225 nm. OH was excited at 291.5 nm in the (1–0), at 313 nm in the (1–1) and at 268.5 nm in the predissociative (3–1) band of the 2Σ–2Π electronic band system, respectively. Prospects of 2D imaging for concentration and temperature measurements in flames using these wavelength extensions are discussed.
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  • 32
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 82.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract OH number densities and rotational temperatures up to 9 bar have been measured using double-phase-conjugate four-wave mixing (DPCFWM) in flat laminar premixed methane/air flames. By phase conjugating the backward pump to the forward pump with a phase-conjugate mirror conventional degenerate four-wave mixing (DFWM) becomes DPCFWM and quantitative measurements of OH radicals and OH rotational temperatures in flames at high pressure are possible. Our results show that conventional DFWM with a standard mirror is a low-biased measurement at high pressure primarly due to a fluctuating interaction volume which results from large fluctuating density gradients at the edge of the flame and from flame movement. A comparison is made between a laser-saturated fluorescence technique, conventional DFWM, and DPCFWM at 1, 5 and 9 bar.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 55 (1992), S. 437-445 
    ISSN: 1432-0649
    Schlagwort(e): 07.60 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have studied second-harmonic generation by 30 ps and 70 ns 10 μm CO2 laser pulses in nonlinear polycrystalline ZnSe, CdTe and GaAs samples. Second-harmonic generation in these materials can limit the amplification of high-power CO2-laser pulses in amplifier chains sealed with these polycrystalline IR-transmission materials. On the other hand, we now demonstrate for the first time that these materials are suited as nonliner elements for autocorrelation measurements on short infrared laser pulses. For such pulse-width measurements polycrystalline materials have an advantage over single crystals, e.g. GaAs, because they are insensitive to misalignement. Furthermore, these polycrystalline optical elements are easier and cheaper to manufacture than single crystal devices. With such polycrystalline materials we were able to realize reliable autocorrelation measurements of 30–300 ps 10 μm optical-free-induction-decay (OFID) laser pulses.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 56 (1993), S. 34-38 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.80 ; 42.60.E
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract All-optical streaking in a cubic nonlinear medium is analyzed theoretically. The model based on the variational method employs the induced phase front distortion on a probe beam. The numerical calculations for a planar inert-gas filled waveguide show that on-line measurements of picosecond pulse durations in the short-wavelength region are possible.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 56 (1993), S. 57-61 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.20 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Mirrorless coherent oscillation in a four-wave mixing arrangement with two phase-conjugate counterpropagating pump waves is studied in a LiNbO3:Fe crystal. Oscillation waves are observed within a wide, but limited angular window where the gain factor takes its maximum value. The spatial structure and the intensities of particular oscillating components vary continuously in time.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 56 (1993), S. 113-117 
    ISSN: 1432-0649
    Schlagwort(e): 33.80 ; 42.65 ; 42.72
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract An intense radiation at 395.0 nm has been observed when lithium vapor is optically pumped in a heat pipe with a pulsed dye laser whose output wavelength is tuned near the Li 2s–4s two-photon resonance transition. The radiation is emitted in the direction along the pump laser beam. It is proposed that the 395.0 nm radiation is mainly generated through three-photon excitation and one-Raman-photon scattering followed by two-cascade (spontaneous) emission. The overall reaction mechanism can be described by a parametric six-wave mixing process. The quantum efficiency of the observed process is estimated to be of the order of 2 × 10−6.
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  • 37
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 51.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A laser beam at two different frequencies separated by 587 cm−1 is focused into pressurized hydrogen (rotational transition energy, 587 cm−1) to generate multi-color stimulated Raman emission. The polarization state and the pulse energy are measured for each generated emission line using linearly and circularly polarized pump beams. The effect of the polarization is discussed by using a parameter characterizing the polarizability of hydrogen and a conservation rule for the angular momentum in four-wave mixing. Many rotational lines are generated with linearly polarized pump beams through a four-wave mixing process. This is in striking contrast to the results obtained by using a single-color circularly polarized pump beam which generates only one rotational line through a conventional stimulated Raman process.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 56 (1993), S. 331-334 
    ISSN: 1432-0649
    Schlagwort(e): 31.20.Nt ; 42.65 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In this paper the enhancement of the values of the cubic molecular hyperpolarizability γ of the nickel benzendithiol system, resulting from the selective addition of acceptor and donor groups to the ligand structure, is presented. The polarization of the molecular electronic structure is calculated by the finite field method. Significant increases in the values of γ are obtained from bridging two p-nitroaniline molecules with the square planar nickel structure. These results show that structures with significant values of x (2) that are derived from the inclusion of donor and acceptor groups might also be included into the ligands of the nickel dithiolene complex to give rise to materials with enhanced values of x (3).
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  • 39
    ISSN: 1432-0649
    Schlagwort(e): 32.00 ; 42.55 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract When mercury atoms, present with a buffer gas (N2 or Ar) in a quartz cell or in a graphite furnace are excited into the 73 S 1 level by means of two pulsed dye lasers tuned at 253.652 nm (61 S o → 63 P 1) and 435.835 nm (63 P 1 → 73 S 1), a laser-like, collimated emission is observed along the axis of the cell at the green mercury line (73 S 1 → 63 P 2), 546.074 nm). This radiation exhibits a pronounced non-linear dependence upon the number density of the mercury atoms in the cell. This behaviour is interpreted as being due to amplified spontaneous emission (ASE), which occurs as a result of the transient population inversion between the 7s 3 S 1 and 6p 3 P 2 o levels. The parameters governing the population inversion can be deduced by applying a rate equation analysis to the atomic system. A time-resolved observation of both ASE and spontaneous fluorescence signals confirms the totally different characteristics of the two emission processes.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 58 (1994), S. 443-445 
    ISSN: 1432-0649
    Schlagwort(e): 42.10 ; 42.65 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Aluminophthalocyanines were encaged in different silica xerogel matrices. Nonlinear reverse-saturable absorption behavior was observed for both nanosecond and picosecond pulse excitation at 532 nm. In order to determine the relaxation paths of the molecules after optical excitation, we measured the evolution of the transmission of a continuous probe beam through the samples following absorption induced by a pump pulse. The transmission recovery was a few tens of microseconds. The fluorescence lifetime was about 10 ns.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 597-600 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 61.30
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The influence of an external quasi-static electric field on the third-order nonlinear optical properties of a nematic liquid crystal has been studied. We demonstrate both in theory and experiment that the cell behaves like a Kerr-Medium. The sensitivity of the cell can be controlled by the applied voltage. If optical feedback is provided by the use of a dielectric mirror, optical bistability can be achieved. The switching behaviour of the cell may also be controlled by the applied voltage.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 63 (1996), S. 47-50 
    ISSN: 1432-0649
    Schlagwort(e): 31.20.Nt ; 42.65 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Excited-State Absorption (ESA), Two-Photon Absorption (TPA) and the third-order polarizability γ(ω;ω,ω, − ω) have been investigated for a model dichloride derivative of a symmetrically substituted benzylidene analine (SBAC), using a multielectron configuration-interaction procedure. The calculations indicate that SBAC exhibits ESA across the visible region of the spectrum, but that it is not as extensive as for molecules such as the phthalocyanines. The magnitude of the third-order polarizability is dominated by resonance enhancement from a very strongA g →B u one-photon absorption. The calculated off-resonance value for γ(ω;ω,ω, − ω) suggests that SBAC is a potential candidate for ultrafast switching applications.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 63 (1996), S. 121-124 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 51.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract More than thirty rotational lines equally spaced by 587 cm−1 are generated simultaneously in the vicinity of the fundamental line by four-wave Raman mixing using a high-power picosecond Ti:Sapphire laser as a pump source and hydrogen as a Raman medium. Since the wavelength of this multifrequency laser emission extends from the near-infrared to the near-ultraviolet, it can be utilized as a tunable light source for picosecond spectroscopy. Because of the wide spectral bandwidth available, this procedure has great potential for the generation of ultrashort laser pulses by mode-locking these emission lines.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 351-360 
    ISSN: 1432-0649
    Schlagwort(e): 42.25.Bs ; 42.65 ; 78.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Doped as well as nominally pure crystals of Lithium Niobate (LiNbO3), ι-Arginine Phosphate (LAP), Lithium Iodate (LiIO3), Potassium Dihydrogen Phosphate (KDP), Lithium Formate (LFM), Beta-Barium Borate (BBO), and lithium tetra borate were grown and investigated for photorefractive effects at ultraviolet wavelengths down to 333 nm. In nominally undoped LiNbO3 crystals strong beam coupling effects were observed. In contrast to the visible we revealed a diffusion-dominated charge transport mechanism based on holes, and a low photovoltaic field in the order of 550 V/cm. With such a crystal we investigated the modulation transfer function of a lensless image projection system based on a phase conjugation scheme. A spatial frequency response beyond 2800 line pairs per millimeter was observed. Photorefractive beam coupling was also obtained in LiIO3. Light-induced scattering was detected in iron-doped LiIO3 whereas as-grown LAP material did not exhibit any observable photorefractive effects. However, 100 kV X-ray irradiation seems to induce material defects which can lead to weak light-induced scattering at 351 nm. In all other above-mentioned materials, doped as well as undoped, light-induced scattering could not be observed. On the other hand, this is appreciated in all the applications where the crystals are used as nonlinear material for optical frequency conversion.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 429-437 
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.55 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We systematically investigate the difference between both actively and passively mode-locked lasers with Gain-at-the-End (GE) and Gain-in-the-Middle (GM) at the example of Nd:YLF lasers. The GE laser generates pulse widths approximately three times shorter than a comparable GM cavity. This is due to enhanced Spatial Hole Burning (SHB) which effectively flattens the saturated gain and allows for a larger lasing bandwidth compared to a GM cavity. We first investigate enhanced SHB by measuring the cw mode spectrum, where we have observed that the mode spacing in GE cavities depends primarily on the crystal length. This was also confirmed for a Nd:LSB crystal, where the pump absorption length was significantly shorter than the crystal length. In mode-locked operation, pulse widths of 4 ps for passive mode locking and 5 ps for active mode locking are demonstrated with GE cavities, compared to 11 ps for passive and 17 ps for active mode locking with GM cavities. Additionally, the time-bandwidth product for the GE cavity is approximately twice the ideal product for a sech2 pulse shape and cannot be improved by dispersion compensation alone, while the GM cavity has nearly ideal time-bandwidth-limited performance. The results for the GM cavity compare well to existing theories taking into account the added effect of pump-power-dependent gain bandwidth which increases the bandwidth of Nd: YLF from 360 to 〉 500 GHz. In a following paper [1] (called Part II) a rigorous theoretical treatment of the effects due to SHB will be presented.
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  • 46
    ISSN: 1432-0649
    Schlagwort(e): 07.60 ; 42.65 ; 33.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A technique using a Fabry-Perot interferometer has been developed to calibrate high-resolution spectra obtained by Coherent Anti-Stokes Raman Spectroscopy (CARS). This technique was used to measure simultaneously the Raman frequency and the Raman signal at each laser shot. We demonstrate the accuracy of the method by measuring theQ(15) line shifts of molecular oxygen due to collisions with oxygen and water vapour.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 409-413 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.55
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The theory of active-passive mode-locked solid-state lasers is developed where the passive mode-locking is achieved by a nonlinear mirror. Steady-state cw numerical solutions are analyzed in detail for the case of a Nd: YAG laser. The steady-state pulse duration can be reduced by an order of magnitude as compared to the pure active mode-locking regime.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 355-359 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The interaction between two strong pump beams and two signal beams is investigated both theoretically and experimentally. It is shown that the frequencies of the beams need to satisfy the relation that the sum of the pump beam frequencies should be equal to the sum of the signal beam frequencies. The gain is shown to depend on the detuning of the pump beams relative to the incident signal beam and on the direction of the signal beam. Maximum gain is obtained when the signal beams bisect the pump beams.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 121-126 
    ISSN: 1432-0649
    Schlagwort(e): 42.55H ; 42.60B ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The limiting processes in the anti-Stokes Raman Laser (ASRL) are investigated in a Tl ASRL system. The detailed mechanisms and dynamics of ASRL action, photoionization, stimulated collision-induced fluorescence, collisional quenching and other radiative processes are determined, showing the competition among these processes for different experimental parameters.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 192-196 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The rotational temperature behaviour in adiabatic jet expansion of molecular nitrogen is investigated over a wide range of stagnation density and nozzle diameter values using coherent anti-Stokes Raman spectroscopy (CARS). Estimates of rotational collisional numbers are made for both (N2+N2) and (N2+Ar) systems. The aspect of cluster formation for both systems is also discussed.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 51 (1990), S. 219-221 
    ISSN: 1432-0649
    Schlagwort(e): 42.80 ; 42.65 ; 42.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In this paper we describe a phase-conjugate scheme in which the pump waves are derived from a distorted optical beam by a spatial filtering technique. Experimental demonstration of this scheme is given for phase-distortion correction. To avoid the problem of back reflection a quasi-real-time reconstruction scheme is adopted. The read out is done with a direct beam from the laser.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 19-21 
    ISSN: 1432-0649
    Schlagwort(e): 42.60K ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Phase conjugated waves (PCW) were generated for the first time by degenerate four-wave mixing with subnanosecond laser pulses in potassium vapour near the D 1 transition at 7699 Å. The light source was a long cavity grazing incidence dye laser. The pulses had a duration of 700–800 ps and a linewidth of 0.2 Å. The experiments were performed in a temperature range of 400–550° C. A maximum reflectivity of 57% has been observed together with temporal pulse shortening. PCW reflectivity has been measured as a function of the temperature, and the backward pump intensity.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 23-28 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 33.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Coherent vacuum ultraviolet (VUV) radiation was generated by four-wave difference frequency mixing (ωVUV=2ω1−ω2) of pulsed dye laser radiation in carbon monoxide (CO). The frequency ω1 was tuned to the C 1Σ+(υ′=0)←X 1Σ+(υ″=0) two-photon transition, while the dye laser frequency ω2 was scaned around 17650 cm−1 which corresponds to the A 1Π(υ=7)«C 1Σ+(υ′=0) transition energy. The VUV intensity was found to be strongly wavelength dependent. The analysis of the spectrum revealed (i) that the VUV intensity was enhanced by the rotational levels of the A 1Π(υ=7) state and (ii) that the off-resonance excitation in the C 1Σ+(υ′=0)←X 1Σ+(υ″=0) two-photon transition greatly contributed to the present four-wave mixing process. The effects of pumping laser detuning, saturation and foreign gases are briefly discussed.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 52 (1991), S. 380-384 
    ISSN: 1432-0649
    Schlagwort(e): 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Sum-frequency mixing (ω3=ω1+ω2) of UV laser radiation (λ1=266 nm and 213 nm) and tunable coherent infrared light (λ2=1.2–2.6 μm) in lithium borate (LBO) generates radiation at short wavelengths (λ3=188–242 nm). The UV radiation at λ1 is produced by the fourth and fifth harmonic of a pulsed Nd-YAG laser. The infrared light is generated with an optical parametric oscillator of beta barium borate. The phase-matching angle Φ is measured as function of λ3 and compared with calculated values. For UV laser radiation at shorter wavelengths (173 nm≦λ1≦213 nm) the calculations predict an extension of the tuning range of the sum-frequency generated at λ3 to wavelengths as short as the LBO transmission cutoff at 160 nm.
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  • 55
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65 ; 78.30
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A two-stage Raman-conversion system pumped with a Q-switched alexandrite laser is proposed for the generation of broadly tunable infrared radiation. The first stage is a high-pressure Raman cell which accepts a pump beam in long-focusing or parallel-beam geometry, while the successive second one is made of a multi-pass Raman cell with repeated focusing. Using a selected combination of vibrational or rotational Raman shifting by H2, a spectrum ranging from 0.75 μm to 15 μm can be covered by this system.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 53 (1991), S. 71-81 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have studied the various nonlinear optical processes that can be described by a fourth-rank χ(3)-tensor: signals of frequency θ in degenerate four-wave mixing (DFWM), harmonics of frequency 2θ and 3θ, and χ(3)-type difference-frequency generation (DFG) with observation of anti-Stokes emission of a signal of frequency 2θ1 — θ2. Structural information in terms of normalized anisotropies is derived in all frequency domains by analysis of the elements of the respective orientation-dependent susceptibility tensor. A novel laser-based technique for the remote orientation analysis of crystalline structures is introduced.
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  • 57
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 68.35
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A wavelength-dependence study of surface second-harmonic generation from Si(111) is presented. Femtosecond laser pulses tuned from 430 nm to 710 nm were used to probe the dispersion characteristics of the nonlinear response from the surface in the vicinity of bulk absorption. Changes in the rotational symmetry and in the phase of the generated second-harmonic signal were observed. An explanation of the observed changes is given based on a simple anharmonic oscillator model [1]
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 58 (1994), S. 97-104 
    ISSN: 1432-0649
    Schlagwort(e): 42.10 ; 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In this paper we examine the nonlinear optical properties of molecular systems undergoing acis-trans photoisomerization process. Such a process gives rise to dynamic photochromism on a picosecond time scale significant for designing a molecular Spatial Light Modulator (SLM). A kinetic analysis of a generalcis-trans nonlinear organic absorber is performed. The analysis is used to derive an expression for the imaginary part of the complex nonlinear molecular index of refraction. The properties of a molecular SLM based on such an absorber are discussed by examining the azo-type molecular system. These calculation predict an optimum contrast ratio and fast on-off switching for the SLM performance, achieved at low read-write laser intensities.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 607-615 
    ISSN: 1432-0649
    Schlagwort(e): 61.30 ; 42.80 ; 42.65 ; 42.82
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Ferroelectric Liquid Crystals (FLCs) are presented which comprise charge-transfer functional groups, such that highly efficient NonLinear Optical (NLO) properties and pronounced ferroelectricity result. By operating the NLO-FLCs in one of the two Bistable states of the Short-pitch Ferroelectric (SPF) conformation, stable, planar waveguides result. The NLO-FLCs exhibit exceptionally large second-order NLO-coefficientsd 22 = 5 pm/V. Moreover, their linear electrooptical effect is shown to be essentially electronic in nature. This renders ultrafast electrooptical modulators with NLO-FLCs feasible.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 60 (1995), S. 61-65 
    ISSN: 1432-0649
    Schlagwort(e): 32.00 ; 42.65 ; 82.50
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A novel method for exciting the two-photon 2p 3 3p 3 P ←2p 4 3 P atomic oxygen transition is reported. The transition energy is provided by the combined photon energies of the second and third Stokes orders of a deuterium-filled Raman shifter pumped by an ArF-excimer laser. The ArF-excimer-pumped Raman shifter performance is characterized and the approach is demonstrated in an atomic oxygen population created by molecular oxygen absorption and predissociation in room air.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 73-80 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.60. Da
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The stimulated Brillouin scattering threshold of focused broad-band XeCl laser radiation depends on the ratio of the coherence length to the Rayleigh range, which is affected by the transverse beam quality. With reduction of the focal length, the threshold decreases first and then reaches a nearly constant value. In addition, the energy reflectivity is increased. On the other hand, pulse shortening occurs and the phase conjugation fidelity is decreased. Separation of single lines from the structured XeCl laser spectrum improves the SBS efficiency.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 127-134 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.65 ; 78.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Three-photon absorption and three-photon-induced excited-state absorption of rutile are studied by transmission measurements using picosecond pulses of a mode-locked Nd: glass laser. The nonlinear absorption limits efficient stimulated Raman scattering. It reduces the efficiency of two-photon absorption of a picosecond probe continuum. Three-photon absorption coefficients, excited-state absorption cross sections, a Raman gain factor, and two-photon absorption cross-section spectra are determined. The arrangementsE⊥c andE ∥c are considered.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 207-211 
    ISSN: 1432-0649
    Schlagwort(e): 42.70.Gz ; 42.30.Va ; 42.40.Kw ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have optically characterized the newly-developed photorefractive crystal KNSBN: Cu by two-wave coupling at visible and near-infrared wavelengths. The effective electrooptic coefficientsξ(k g)r 13 andξ(k g)r 33, the effective charge carrier densityN eff, the dark conductivityσ d, the product of mobility and electron-trap recombination timeμτ R, the formation and decay rate of index grating and the absorption coefficientα of the crystal were determined from visible to near-infrared wavelengths. Their wavelength dependences were also studied. It is interesting to notice that the KNSBN: Cu crystal has a very largeN eff and large gain coefficientΓ for ordinary ray (o-ray) in the visible region, and the photorefractive properties of the crystal are very different in the visible and near-infrared spectral regions.
    Materialart: Digitale Medien
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  • 64
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65 ; 82.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In this paper, the design and performance characteristics of a pulsed tunable dye laser system for the simultaneous generation of two UV wavelengths are presented. The system is composed of an oscillator and an amplifier stage, pumped by the second harmonic of a commercial Nd:YAG laser. Dual-wavelength operation is achieved with one additional tuning mirror introduced to the prism expanded grazing incidence oscillator. The two obtained wavelengths are independently tunable, their separation is only limited by the gain profile of the dye. Both wavelengths are frequency doubled by Second-Harmonic Generation (SHG) in two KDP or BBO crystals. Performance characteristics such as bandwidth, efficiency, tuning range and wavelength separation are reported. As application two such systems are used for the simultaneous detection of the four elements cadmium, nickel, manganese and lead by Laser-Excited Atomic Fluorescence Spectrometry in a graphite furnace (ETA-LEAFS).
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 62 (1996), S. 39-44 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 33.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Thermometry of an oxy-acetylene flame using multiplex Degenerate Four-Wave Mixing (DFWM) of C2 is demonstrated. More than 100 rotational transitions in thed 3 Π g ←a 3 Π u (0,0) Swan band of C2 could be recorded simultaneously by use of a pulsed, broad bandwidth “modeless” laser. Temperatures were inferred by fitting temperature-dependent synthetic spectra of single- or multiple-shot averaged spectra. The strength and reliability of recorded signals together with the large number of rotational lines observed suggest that multiplex DFWM is a promising technique for minor species detection and for temporally resolved temperature measurements in luminous environments. Factors influencing the accuracy and precision of single-shot thermometry using the technique are discussed.
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 511-514 
    ISSN: 1432-0649
    Schlagwort(e): 42.30 ; 42.40 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We consider the possibility of restoration and/or enhancement of decaying holograms in photorefractive media by using a simple optical readout in conjunction with a phase conjugator. The results indicate that extremely weak holograms can be enhanced provided that the two-beam coupling is sufficiently strong. Steady-state photorefractive holograms can be maintained continuously without decay by using a self-enhanced readout scheme. The results also provide an explanation for the formation of mutually pumped phase conjugation in terms of the amplification of an initial noise grating. The results are presented and discussed.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 247-258 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The standard four wave mixing model in a sluggish photorefractive medium is used to calculate the transient response of a phase conjugate resonator. General trends are unveiled and discussed in view of the possible use of the system in image processing. Experimental results are shown to confirm qualitatively the predicted behaviour.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 62 (1996), S. 479-483 
    ISSN: 1432-0649
    Schlagwort(e): 78.30 ; 78.32 ; 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A design of a compact blue-green stimulated Raman shifter pumped by the third harmonic of a Nd:YAG laser is presented. Design parameters given here are based on our experimental investigation of various optimization techniques involving parametric studies. Blue-green energy conversion of up to 66% is achieved. The problem of optical breakdown is addressed.
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  • 69
    ISSN: 1432-0649
    Schlagwort(e): 36.40 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The hot luminescent reaction zones of CO2-laser-induced pyrolysis flames using SiH4/C2H2 gas mixtures with different silane to acetylene ratios and with and without diborane additives were investigated by means of H2 Q-branch CARS spectroscopy, leading to spatial temperature profiles in gas flow direction. In the case of B2H6 additive to the stoichiometric SiH4/C2H2 mixture a high temperature plateau (≈ 800–1000 K) of the reactant gas volume develops already several millimetres before reaching the CO2-laser focus line. This precursor preheating zone could be explained by the catalytic effect of boron atoms or boron-containing intermediate species in the flame. A similar behaviour for acetylene-rich flames operating at half laser power was not observed.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 63 (1996), S. 145-150 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Guiding of multiple signal beams in an induced all-optical cable is studied theoretically. A balance relation is derived for the interaction geometry and undistorted propagation of bright elliptical signal beams nested in a single ring dark soliton. The numerical analyses show a remarkable misalignment stability of the parallel guiding scheme.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 63 (1996), S. 117-120 
    ISSN: 1432-0649
    Schlagwort(e): 42.60B ; 42.60D ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Narrow linewidth, single spectral mode operation has been obtained in a high power, 810 nm broad-area diode laser in an extended cavity configuration with a grating as external reflector (grating feedback). For stable operation it was necessary to misalign the feedback slightly in the plane of the laser junction. Characteristics of the thus obtained laser system are a linewidth below 5 MHz, an output intensity of about 50% of the free running power, a large-scale tuning range of 15 nm and continuous scanning over 4 GHz. In the spatial domain, the laser remains multimode and astigmatic. To show the practical applicability of this system, saturated absorption of a krypton line is demonstrated.
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  • 72
    ISSN: 1432-0649
    Schlagwort(e): 33.00 ; 42.55 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The effect of Mid-InfraRed (MIR) (λ ≅ 12 μm) and Far-InfraRed (FIR) (λ ≽ 100 μm) emission from excited ammonia on the absorption of intense radiation of a TEA CO2 laser has been studied experimentally under collisional and collisionless excitation conditions with ammonia pressures from 0.5 to 0.03 Torr. The energy of MIR and FIR emission was studied as a function of NH3 pressure and laser energy fluence. Particular emphasis was given to the kinetics of MIR and FIR emission generation at different NH3 pressures and to the measurement of the time delay of re-emitted pulses relative to the exciting CO2 laser pulse. It has been found that the re-emission in the MIR range is highly collisional in nature. The intensity of MIR emission drops sharply (asp 3) with decreasing NH3 pressure and its delay time relative to the exciting laser pulse increases. At the same time, re-emission in the FIR range (in the case of resonant excitation of NH3 at the 9R (30) line of CO2 laser) is observed during an exciting pulse up top 〈 0.03 Torr. When binding the rotational sub-levels of a molecule with transitions, FIR emission acts as rotational relaxation and thus leads to an increase in NH3 IR absorption even at collisionless excitation.
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  • 73
    ISSN: 1432-0649
    Schlagwort(e): 7.65 ; 33.00 ; 42.60 ; 42.65 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A new widely tunable source in the infrared for use in high-resolution spectroscopy and trace-gas detection is described. This spectroscopic source is based on Difference Frequency Generation (DFG) in gallium selenide (GaSe) and is continuously tunable in the 8.8–15.0 μm wavelength region. Such a DFG source operates at room temperature which makes it a useful alternative to a lead-salt diode-laser- based detection system that requires cryogenic temperatures and numerous individual diode lasers.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 1-5 
    ISSN: 1432-0649
    Schlagwort(e): 32.80 ; 42,50 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The synchronization of atomic quantum transitions with natural Raman oscillations by ultrashort light pulses has been investigated. This phenomenon may be observed if the duration of the perturbation pulse is less than the period of oscillations of the forbidden atomic transitions. The accuracy of the direct measurements of the quantum transition times for trapped particles can be of the same order as the ratio of the two-photon transition frequency to the homogeneous line width.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 319-322 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.40 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A new type of anisotropic scattering with ring-and-line structure is observed for the first time from a BaTiO3 crystal illuminated by a linearly polarized laser beam. The analysis presented herein is based on the photorefractive four-wave interaction of the incident, reflected, and scattered beams. The experimental results agree well with the theoretical analysis.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 331-344 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.72
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Resonant third-order sum-frequency mixing of continuous-wave visible and ultraviolet laser light is investigated in the metal vapors of Sr, Ca, Mg, and Zn. The laser radiation (with the frequencies ω1, ω2, and ω3) is generated by single-mode dye- and argonion lasers. The third-order nonlinear susceptibility is enhanced by tuning the laser frequencies 2ω1 or ω1+ω2 to a two-photon resonance. The wavelength of the generated coherent VUV radiation (with the frequency ωVUV=3ω1, ωVUV=2ω1+ω2 or ωVUV=ω1+ω2+ω3) is tunable in spectral regions between 133 and 217 nm. For most conversion processes an additional enhancement of the nonlinearity is provided by an autoionizing level or by a highly excited state close to E=ħωVUV. With laser powers of 0.2–3 W the power of the generated sum frequencies is in the range of 5×105–6×1010 photons s−1 (0.5 pW–60 nW).
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 39-46 
    ISSN: 1432-0649
    Schlagwort(e): 33.10.Jz ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A systematic study of the influence of the collisional narrowing and the cross coherence effect on the temperature analysis of N2-Q branch-CARS spectra at atmospheric pressure is presented. A comparison of calculated spectra over a temperature range 300–2000 K reveals that the standard theory neglecting these effects leads to temperature errors of +1.7% under flame conditions, when the nonresonant background is suppressed. This result is supported by the analysis of experimental CARS temperature measurements on a standard laminar diffusion flame. Furthermore, the temperature misreadings originating from erroneous slit function parameters and laser linewidth were investigated.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 50 (1990), S. 47-50 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Semiconductor nonlinear Fabry-Perot etalon design is considered. A method of determination of cavity parameters simultaneously satisfying the requirements: low critical switching intensity, high output signal and high contrast between two stable state, is proposed. The results obtained may be used for construction of optical bistable elements in the transmission operation mode.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 58 (1994), S. 171-181 
    ISSN: 1432-0649
    Schlagwort(e): 42.55.Rz ; 42.60.Fc ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The techniques of coupled-cavity modelocking and self-modelocking in which intensity-induced nonlinear effects are exploited have been reviewed for broad-band gain media. Particular emphases have been placed upon the archetypical colour-centre and titanium-sapphire laser configurations in which these techniques were first demonstrated and subsequent refinements are set in context. A femtosecond optical parametric oscillator pumped by a self-mode-locked titanium-sapphire laser has also been described as an exemplar of a practical means of extending the source tunability into the mid-infrared spectral region.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 58 (1994), S. 317-321 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The nonlinear surface susceptibility χ S (2) is generally referred to the system of Cartesian coordinates of thesample. However, since actual measurements take place with respect to thelaboratory system of coordinates, appropriate transformation of χ S (2) is necessary to deduce the underlying susceptibility-components. We demonstrate this by analyzing the second-harmonic signal generated by an inclined sample upon rotation around thes-axis of the laboratory system of coordinates. The sample consists of two Langmuir-Blodgett-type monolayers of rotational symmetry around the sample normal, the two layers being separated by a plane-parallel flat of 1 mm thickness. The occurrence of a “symmetry-forbidden”I SS 2ω -signal is discussed in detail.
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  • 81
    ISSN: 1432-0649
    Schlagwort(e): 42.70 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report on the spectral properties and numerical modelling of a singly resonant Optical Parametric Oscillator (OPO) of Lithium-triBOrate (LBO). The OPO is pumped by the second, third or fourth harmonic of an injection-seeded,Q-switched Nd:YAG laser. The measured OPO parameters are the tuning range, the threshold, the spectral linewidth, the efficiency and the output power. For the LBO-OPO critical type-I phase-matching (xy-plane) provides a wide tuning range and optimum values of the effective nonlinear coefficient. Pumped, for example, by the 355nm third harmonic the spectral range extends from 414 nm to 2.47 µm. With a 15 mm long crystal the OPO generates a total output-pulse energy of 77 mJ with an efficiency of 45%. For 266 nm pump radiation the signal wave is in the near ultraviolet at 307–325 nm. If pumped at 532 nm the OPO generates simultaneously two pairs of signal and idler waves in the infrared (0.707–2.15 µm). The pulse-energy fluctuations of the two pairs are correlated. If, however, the OPO is injection-seeded at one of the signal waves the two wavelength pairs are anti-correlated. The observed wavelength tuning as well as the measured spectral line-widths, threshold energies and efficiencies are in agreement with the values predicted by computer simulation.
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  • 82
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.70 ; 42.82
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Guided-wave second-harmonic generation using a passive planar waveguide covered with an organic nonlinear optical film as thin as a single molecular layer is demonstrated. The phase-matching condition of this process is revealed both with a high degree of waveguide-mode selectivity and a maximum in the frequency response.
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 203-209 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The anisotropy ofχ (3) in Poly-bis(p-Toluene Sulfonate) of 2.4-hexadiyne-1.6-diol (PTS) PolyDiAcetylene (PDA) single crystals is investigated by Degenerate Four-Wave Mixing (DFWM) at a wavelength of 720 nm. The symmetries ofχ (3)(−ω;ω, −ω,ω) identify the non-vanishing and independent components of the tensor. For the calculation of the χ(3) elements from the measured values, the anisotropy of both the linear optical index of refraction and the absorption coefficient is included in the coupled wave approach. A magnitude of 10−10 esu is measured for theχ (3) component if all beam polarizations are parallel to the polymer chains. The least upper bound for all other measurable components is estimated to be 10−12 esu. The results for the intensity dependence of the DFWM signal are explained in terms of a thermooptic effect. Measurements on the orientational dependence of the DFWM signal in the samples are carried out, and the influence of the anisotropy of the linear optical parameters on the measured curves is discussed. A method for the preparation of thin layered polymer single crystals of poly-bis (4-ButoxyCarbonyle-Methylene-Urethane) of 4.6-decadiyne-1.1-diol (4-BCMU) and the first DFWM measurements on these samples are presented.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 467-470 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.80 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We theoretically analyze the properties of Fabry-Perot etalons which consist of photorefractive-crystal plates with asymmetric mirror reflectance. Peak transmissions and non-reciprocities are enhanced significantly compared with the symmetric photorefractive etalons. The effect of material absorption is also considered.
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  • 85
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 32.00
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Near-UV radiation is generated by doubling the frequency of a semiconductor laser in a nonlinear crystal. The crystal is contained in a resonant cavity in order to improve the conversion efficiency. The cavity increases the efficiency by about three orders of magnitude. This radiation has been used to perform spectroscopy of metastable magnesium in an atomic beam. We observed the (3s3p)3 P−(3s3d)3 D transition multiplet, which is of interest for metrological applications. The isotopic shift between24Mg and26Mg was measured and new information on the hyperfine structure of25Mg was obtained. This radiation source is promising also in order to improve the Mg frequency standard.
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  • 86
    ISSN: 1432-0649
    Schlagwort(e): 42.80 ; 42.30 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Color phase-conjugate imaging is demonstrated using a multi-colored laser beam. Speed of response, size of the image, clarity of the image, and the intensity of the image are investigated. Color images are stored and recalled without crosstalk between different colors.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 53 (1991), S. 350-352 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.70 ; 42.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report an experimental measurement, based on an interferometric technique, for the determination of the temperature dependence of the refractive index n L of a liquid suspension of dielectric spheres in the thermal range 20–52° C. In this range we have measured values of ∂n L /∂T of order of magnitude 10−4° C−1. The observed values are compared with those obtained for water.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 49-57 
    ISSN: 1432-0649
    Schlagwort(e): 33.20 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract To establish H2 CARS thermometry at high pressure, accumulated H2 Q-branch CARS spectra were recorded in the exhaust of a fuel-rich CH4/air flame at pressures between 5 and 40 bar. Temperatures were deduced by fitting theoretical spectra to experimental data points. The Energy-Corrected Sudden (ECS) scaling law was employed to set up an empirical model for the calculation of H2 linewidths in high-pressure hydrocarbon flames with H2 as a minority species. Experimental H2 CARS spectra could be simulated very accurately with this model. The evaluated temperatures agreed well with reference temperatures obtained by spontaneous rotational Raman scattering of N2.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 103-108 
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The accuracy of CARS thermometry for H2O vapour has been assessed under carefully controlled conditions for the temperature range 295 to 900 K and the pressure range 0.0066 to 2.7 atm. Excellent agreement between theory and experiment was achieved for line-broadening regimes ranging from Doppler broadening to motional narrowing. Various models for rotational energy transfer and line-broadening were compared and where pressure broadening dominated, excellent agreement was achieved with a simple linewidth model, dependent only on temperature and pressure. Excellent agreement was also achieved using either energy or angular momentum based relaxation models to model motionally narrowed spectra in the pressure range up to 2.7 atm. However, good agreement between theory and experiment depended on the inclusion of state mixing correction factors, and good thermometry accuracy at high temperature was sensitive to the value assumed for the water molecular polarisability.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 113-118 
    ISSN: 1432-0649
    Schlagwort(e): 78.20 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report a theoretical model for an estimate of carrier-induced changes in the refractive index of InSb at room temperature. The dispersion of Δn within the photon-energy interval of 0.12–0.24 eV is investigated for nonequilibrium carrier concentrations of 1015–1018 cm−3. An analysis of the influence of the initial carrier density on Δn is performed. The obtained results can help to develop InSb opto-electronic devices.
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  • 91
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract After having reported preliminary results related to saturation, we first theoretically consider the various mechanisms contributing to the resonant optical Kerr effect in Cd(S, Se)-doped glasses. We obtain the expression for the expected effective susceptibility in different possible cases. This nonlinearity is studied experimentally using optical-phase conjugation in the low-intensity regime. We show that, by time resolving the nonlinear response of such glasses having experienced various degrees of photodarkening, we can clearly assess the origin of the resonant optical Kerr effect in these materials. Usually, a combination of a fast free-carrier contribution due to particles without traps and of a slow trapped-carrier one due to particles with traps is observed. For the free-carrier contribution, induced absorption is observed to be almost as important as absorption saturation. We also report frequency-dependent measurements and discuss the change in absorption spectrum and the increase of the nonradiative decay rate that accompany darkening.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 184-187 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.10
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A set of formulae have been developed for calculations of the optical characteristics of droplets under conditions of whispering gallery mode (WGM) excitation. The WGM excitation is shown to cause the ripple structure in the Mie extinction cross section. The Chýlek equation for the distance between two neighboring morphology-dependent resonances (MDRs) in a spectrum has been revised. The equation is presented for the spherical-resonator finesse allowing for light scattering on inhomogeneities of the resonator surface, etc. A comparison of the theory and data in the literature is made and some peculiarities of spectra are explained.
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 213-215 
    ISSN: 1432-0649
    Schlagwort(e): 42.55 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Energy output of 400 mJ, an order of magnitude higher than reported previously is obtained in aQ-switched flashlamp-pumped Nd3+:KGd(WO4)2 laser. No pronounced saturation of the output energy with respect to the pump energy is observed. Multiwavelength operation due to efficient Stokes conversion in the laser crystal is demonstrated.
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  • 94
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 42.55 ; 07.60 ; 07.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We have investigated the increase of efficiency for high-order anti-Stokes Raman scattering using a cryogenic Raman cell. By cooling the cell to liquid-nitrogen temperature, output energies of the 9th-order anti-Stokes wave at 133 nm in normal hydrogen were enhanced by a factor of 10, and the 11th-order anti-Stokes line at 141 nm in normal deuterium appeared, while no output was observed at room temperature. No output energy enhancement, however, was obtained using cooled para-hydrogen as a result of multiple rotational Raman scattering. For long-term operation, the output window surface of the Raman cell was kept at above 200 K in order to protect it from deposition, the absorption of which is detrimental to VUV transmission.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 61 (1995), S. 415-419 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 72.40 ; 78.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report on the observation of mirrorless oscillation in photorefractive BaTiO3 pumped by two pairs of two nearly counterpropagating light waves, each of them containing an ordinary and an extraordinary component of polarization. The oscillation waves are located on a cone with an apex angle defined by the phase-matching conditions of this process.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 288-294 
    ISSN: 1432-0649
    Schlagwort(e): 42.60 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Systematic experimental observations of axially phase-matched parametric four- and sixwave mixing processes have been made in potassium vapor pumped on or near the 4S–6S two-photon resonance. An IR up-conversion with a beta barium borate crystal was used for the detection of IR emissions. All the predicted processes have been observed. It is found that the excitation spectra of the emissions for those processes observed in this work are quite different from the excitation spectra of similar processes in sodium vapor. A dye-dependence of some emissions generated by the axially phase-matched parametric six-wave mixing processes has been found by using different dyes in the dye laser. The reason for the dye-dependence is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 54 (1992), S. 317-318 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 33.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 60 (1995), S. 437-442 
    ISSN: 1432-0649
    Schlagwort(e): 42.55 ; 42.65 ; 42.60
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The design, configuration and operation of Ti:Sapphire-laser-pumped femtosecond Optical Parametric Oscillators (OPOs) using KTP and RTA are described. The results presented include configurations capable of producing transform-limited pulses shorter than 40 fs and operating with pump powers as low as 50 mW. Tunability within the 1–3 µn spectral region is demonstrated using pump-tuning alone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    ISSN: 1432-0649
    Schlagwort(e): 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Efficient generation of femtosecond pulses in the wavelength range from 520 to 675 nm by external frequency doubling the signal wave of a non-critically phase-matched picosecond KTP Optical Parametric Oscillator (OPO) in a non-critically phase-matched temperature tuned LiB3O5(LBO) crystal is demonstrated. An average power of the second harmonic as high as 310 mW at 575 nm was generated. In the absence of group velocity mismatch of LBO for a wavelength of the OPO at about 1.3 µm the minimum second-harmonic pulse width was 400 fs at 645 nm.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 60 (1995), S. 571-572 
    ISSN: 1432-0649
    Schlagwort(e): 42.65 ; 72.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A theoretical model of a transient nonlinear four-photon interaction in a fibre is proposed. An optimization of the efficiency of the parametric conversion is suggested.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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