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Narrow-Linewidth Megahertz-Repetition-Rate Optical Parametric Oscillator For High-Speed Flow And Combustion Diagnostics, Naibo Jiang, Walter R. Lempert, Gary L. Switzer, Terrence R. Meyer, James R. Gord
Narrow-Linewidth Megahertz-Repetition-Rate Optical Parametric Oscillator For High-Speed Flow And Combustion Diagnostics, Naibo Jiang, Walter R. Lempert, Gary L. Switzer, Terrence R. Meyer, James R. Gord
Terrence R Meyer
We demonstrate the ability to generate ultra-high-frequency sequences of broadly wavelength-tunable, high-intensity laser pulses using a custom-built optical parametric oscillator pumped by the thirdharmonic output of a "burst-mode" Nd:YAG laser. Burst sequences consisting of 6-10 pulses separated in time by 6-10 Îs are obtained, with average total conversion efficiency from the 355 nm pump to the near-IR signal and idler wavelengths of 33%. Typical individual pulse output energy for the signal and idler beams is in the range of 4-6 mJ, limited by the available pump energy. Line narrowing is demonstrated by means of injection seeding the idler wave using …
Measurements Of Oh Mole Fraction And Temperature Up To 20 Khz By Using A Diode-Laser-Based Uv Absorption Sensor, Terrence Meyer, Sukesh Roy, Thomas Anderson, Joseph Miller, Vlswanath Katta, Robert Lucht, James Gord
Measurements Of Oh Mole Fraction And Temperature Up To 20 Khz By Using A Diode-Laser-Based Uv Absorption Sensor, Terrence Meyer, Sukesh Roy, Thomas Anderson, Joseph Miller, Vlswanath Katta, Robert Lucht, James Gord
Terrence R Meyer
Diode-laser-based sum-frequency generation of ultraviolet (UV) radiation at 313.5 nm was utilized for high-speed absorption measurements of OH mole fraction and temperature at rates up to 20 kHz. Sensor performance was characterized over a wide range of operating conditions in a 25.4 mm path-length, steady, C2H4-air diffusion flame through comparisons with coherent anti-Stokes Raman spectroscopy (CARS), planar laser-induced fluorescence (PLIF), and a two-dimensional numerical simulation with detailed chemical kinetics. Experimental uncertainties of 5% and 11% were achieved for measured temperatures and OH mole fractions, respectively, with standard deviations of <3% at 20 kHz and an OH detection limit of <1 part per million in a l m path length. After validation in a steady flame, high-speed diode-laser-based measurements of OH mole fraction and temperature were demonstrated for the first time in the unsteady exhaust of a liquid-fueled, swirl-stabilized combustor. Typical agreement of 5% was achieved with CARS temperature measurements at various fuel/air ratios, and sensor precision was sufficient to capture oscillations of temperature and OH mole fraction for potential use with multiparameter control strategies in combustors of practical interest.
Diode-Laser-Based Ultraviolet-Absorption Sensor For High-Speed Detection Of The Hydroxyl Radical, Thomas N. Anderson, Robert P. Lucht, Terrence R. Meyer, Sukesh Roy, James R. Gord
Diode-Laser-Based Ultraviolet-Absorption Sensor For High-Speed Detection Of The Hydroxyl Radical, Thomas N. Anderson, Robert P. Lucht, Terrence R. Meyer, Sukesh Roy, James R. Gord
Terrence R Meyer
A new diode-laser-based UV-absorption sensor for high-speed detection of the hydroxyl radical (OH) is described. The sensor is based on sum-frequency generation of UV radiation at 313.5 nm by mixing the output of a 763-nm distributed-feedback diode laser with that of a 532-nm high-power, diode-pumped, frequency-doubled Nd:YVO4 laser in a B-barium borate crystal.