A compact, high-speed tunable, diode-laser-based mid-infrared (MIR) laser source has been developed for absorption spectroscopy of CO2 at rates up to 10 kHz. Radiation at 4.5 µm with a mode-hop-free tuning range of 80 GHz is generated by difference-frequency mixing the 860 nm output of a distributed-feedback diode laser with the 1064 nm output of a diode-pumped Nd:YAG laser in a periodically poled lithium niobate crystal. MIR absorption spectroscopy of CO2 with a detection limit of 44 ppm at 10 kHz is demonstrated in a C2H4-air laminar diffusion flame and in the exhaust of a liquid-fueled model gas-turbine combustor.
© 2005 Optical Society of America
(120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
(140.2020) Lasers and laser optics : Diode lasers
(190.1900) Nonlinear optics : Diagnostic applications of nonlinear optics
(300.1030) Spectroscopy : Absorption
(300.6260) Spectroscopy : Spectroscopy, diode lasers
Terrence R. Meyer, Sukesh Roy, Thomas N. Anderson, Robert P. Lucht, Rodolfo Barron-Jimenez, and James R. Gord, "10 kHz detection of CO2 at 4.5 µm by using tunable diode-laser-based difference-frequency generation," Opt. Lett. 30, 3087-3089 (2005)