A frequency-locked, injection-seeded, pulsed optical parametric generator (OPG) has been developed for short-range infrared differential absorption lidar (DIAL) applications. The periodically poled lithium niobate OPG is pumped by a passively <i>Q</i>-switched Nd:YAG microlaser and is seeded by a distributed feedback (DFB) diode laser. The OPG is designed for DIAL measurement of a narrow <i>R</i>-branch transition of methane at 3.2704 μm. The output of the OPG is a two-pulse sequence with a 100-μs temporal separation between the pulses, where the first pulse is absorbed by methane and the second pulse is not absorbed. The first pulse is actively locked to the methane absorption feature by use of the derivative of the transmission spectrum through a reference cell. Although the device was not optimized for output power, the 3.27-μm OPG output energies of the first and second pulses are 5.5 and 5.9 μJ, respectively, producing 21 mW when operated at 1818 Hz.
© 2003 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4970) Nonlinear optics : Parametric oscillators and amplifiers
(280.1910) Remote sensing and sensors : DIAL, differential absorption lidar
Thomas A. Reichardt, Ray P. Bambha, Thomas J. Kulp, and Randal L. Schmitt, "Frequency-Locked, Injection-Seeded, Pulsed Narrowband Optical Parametric Generator," Appl. Opt. 42, 3564-3569 (2003)