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  • 1
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    Pulsed injection control of a titanium-doped sapphire laser (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Injection control of a tunable Ti:sapphire laser using a narrow-bandwidth pulsed dye laser operating at a wavelength removed from the peak of the Ti:sapphire-laser gain curve is reported. The free-running Ti:sapphire laser had broadband laser emission from 750 to 790 nm. Injection at 727 nm resulted in essentially complete energy extraction at that wavelength in a 2.5-pm bandwidth matching the injection source.
    Keywords: LASERS AND MASERS
    Type: Optics Letters (ISSN 0146-9592); 11; 712-714
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    NASA TECHNICAL REPORTS
  • 2
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    Demonstration of frequency control and CW diode laser injection control of a titanium-doped sapphire ring laser with no internal optical elements (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Theoretical and experimental frequency narrowing studies of a Ti:sapphire ring laser with no intracavity optical elements are reported. Frequency narrowing has been achieved using a birefringent filter between a partially reflecting reverse wave suppressor mirror and the ring cavity output mirror. Results of CW diode laser injection seeding are reported.
    Keywords: LASERS AND MASERS
    Type: IEEE Journal of Quantum Electronics (ISSN 0018-9197); 24; 1045-104
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    NASA TECHNICAL REPORTS
  • 3
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    Absorption and fluorescence of alexandrite and of titanium in sapphire and glass (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The fluorescence and absorption data for titanium in crystalline sapphire and titanium doped into two silicate and one phosphate glass structures are analyzed. It is observed that the Ti-doped silicate glass sample exhibits no absorption related to the Ti(III) ion, the Ti-doped phosphate glass is deep blue, the absorption line width of the glass samples are a factor of two larger than that of sapphire, and the absorption peak for the Ti in the glass shifted about 100 nm to the red from the Ti:sapphire absorption peak. This shift reveals that the Ti(III) ion is sensitive to the crystalline environment and not to the glass environment. The photoluminescence spectra for Ti-doped sapphire and alexandrite are compared. It is detected that the Ti:sapphire exhibits a broader spectrum than that for alexandrite with a peak at 750 nm. The three zero phonon transitions of Ti:Al2O3 at liquid nitrogen temperatures are studied.
    Keywords: LASERS AND MASERS
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    NASA TECHNICAL REPORTS
  • 4
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    Rare isotope studies involving catalytic oxidation of CO over platinum-tin oxide (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Results of studies utilizing normal and rare oxygen isotopes in the catalytic oxidation of carbon monoxide over a platinum-tin oxide catalyst substrate are presented. Chemisorption of labeled carbon monoxide on the catalyst followed by thermal desorption yielded a carbon dioxide product with an oxygen-18 composition consistent with the formation of a carbonate-like intermediate in the chemisorption process. The efficacy of a method developed for the oxygen-18 labeling of the platinum-tin oxide catalyst surface for use in closed cycle pulsed care isotope carbon dioxide lasers is demonstrated for the equivalent of 10 to the 6th power pulses at 10 pulses per second.
    Keywords: LASERS AND MASERS
    Type: Closed-Cycle, Frequency-Stable CO2 Laser Technology; p 193-197
    Format: application/pdf
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  • 5
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    Catalysts for long-life closed-cycle CO2 lasers (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin (IV) oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-LaRC on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) achievement of 98% to 100% conversion of a stoichiometric mixture of CO and O2 to CO2 for 318 hours (greater than 1 x 10 to the 6th power seconds), continuous, at a catalyst temperature of 60 C, and (2) development of a technique verified in a 30-hour test, to prevent isotopic scrambling when CO-18 and O-18(2) are reacted in the presence of a common-isotope Pt/Sn O-16(2) catalyst.
    Keywords: LASERS AND MASERS
    Type: Closed-Cycle, Frequency-Stable CO2 Laser Technology; p 113-119
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  • 6
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    Application of an InGaAsP diode laser to probe photodissociation dynamics - I(asterisk) quantum yields from n- and i-C3F7I and CH3I by laser gain vs absorption spectroscopy (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Initial measurements on I-asterisk yields of alkyl iodides at 266 nm are reported using gain vs. absorption spectroscopy with an InGaAsP diode probe laser. The results are 102 percent + or - 4 percent, 102 percent + or - 7 percent, and 73 percent + or - 4 percent for n-C3F7I, i-C3F7I, and CH3I respectively. Future prospects for the development of diode laser systems and for their use in dynamical studies are discussed.
    Keywords: LASERS AND MASERS
    Type: Journal of Chemical Physics (ISSN 0021-9606); 84; 2143-214
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  • 7
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    Absolute 1* quantum yields for the ICN A state by diode laser gain versus absorption spectroscopy (1987)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Absolute I* quantum yields were measured as a function of wavelength for room temperature photodissociation of the ICN A state continuum. The temperature yields are obtained by the technique of time-resolved diode laser gain-versus-absorption spectroscopy. Quantum yields are evaluated at seven wavelengths from 248 to 284 nm. The yield at 266 nm is 66.0 +/- 2% and it falls off to 53.4 +/- 2% and 44.0 +/- 4% at 284 and 248 respectively. The latter values are significantly higher than those obtained by previous workers using infrared fluorescence. Estimates of I* quantum yields obtained from analysis of CN photofragment rotational distributions, as discussed by other workers, are in good agreement with the I* yields. The results are considered in conjunction with recent theoretical and experimental work on the CN rotational distributions and with previous I* yield results.
    Keywords: LASERS AND MASERS
    Type: NASA-CR-180344 , NAS 1.26:180344
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    NASA TECHNICAL REPORTS
  • 8
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    Recent advances in efficient long-life, eye-safe solid state and CO2 lasers for laser radar applications (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-27
    Description: The key problems in the development of eye-safe solid-state lasers are discussed, taking into account the energy transfer mechanisms between the complicated energy level manifolds of the Tm, Ho, Er ion dopants in hosts with decreasing crystal fields such as YAG or YLF. Optimization of energy transfer for efficient lasing through choice of dopant concentration, power density, crystal field and temperature is addressed. The tailoring of energy transfer times to provide efficient energy extraction for short pulses used in DIAL and Doppler lidar is considered. Recent advances in Pt/SnO2 oxide catalysts and other noble metal/metal oxide combinations for CO2 lasers are discussed. Emphasis is given to the dramatic effects of small quantities of H2O vapor for increasing the activity and lifetime of Pt/SnO2 catalysts and to increased lifetime operation with rare isotope (C-12)(O-18)2 lasing mixtures.
    Keywords: LASERS AND MASERS
    Type: Laser Radar III; Sept. 6-7, 1988; Boston, MA; United States
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    NASA TECHNICAL REPORTS
  • 9
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    Research on catalysts for long-life closed-cycle CO2 laser oaperation (1987)
    In:  Other Sources
    Details
    Publication Date: 2019-07-27
    Description: Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin-oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-Langley on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) the effects of various catalyst pretreatment techniques on catalyst efficiency; (2) development of a technique, verified in a 30-hour test, to prevent isotopic scrambling when C(O-18) and (O-18)2 are reacted in the presence of a common-isotope Pt/Sn(O-16)2 catalyst; and (3) development of a mathematical model of a laser discharge prior to catalyst introduction.
    Keywords: LASERS AND MASERS
    Type: Laser radar II; May 19, 20, 1987; Orlando, FL; United States
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    NASA TECHNICAL REPORTS
  • 10
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    Transient gain-versus-absorption laser probing of spin-orbit states, kinetics and dynamics (1986)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The spin-orbit populations of excited (2P1/2) and ground (2P3/2) state Br atoms at 2714 nm and I atoms at 1315 nm are examined using a tunable F-center laser and a diode laser. The transient laser gain-versus-absorption measurements are utilized to estimate quantum yields of the spin-orbit states in the photodissociation of Br- and I-containing compounds; the continuum yields for Br2 are investigated in terms of temperature. The collisional release, Doppler velocity effects, and differing reactivity of the spin-orbit excited and ground state atoms are studied. It is noted that the transient gain versus absorption technique is applicable to the analysis of kinetic phenomena due to its high sensitivity and excellent time resolution.
    Keywords: LASERS AND MASERS
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