Abstract

Differential backscatter absorption gas imaging (BAGI) of methane¹ requires a pulsed laser source that can be rapidly tuned on and off a methane absorption feature. A pulsed, seeded periodically poled lithium niobate (PPLN) optical parametric generator (OFG) has been developed for incorporation into a handheld differential BAGI instrument. The OPG is pumped by a single-longitudinal-mode 1.064-μm passively Q- switched Nd:YAG microlaser and is seeded by a 1.577-μm distributed feedback (DFB) diode laser. The resulting 3.2704-μm idler radiation overlaps a narrow R-branch absorption feature of methane. The OPG provides approximately 10% conversion of the 1064-nm pump to the infrared idler wavelength over a broad range of pump energies, similar to the efficiencies reported by Bader et al.²

© 2002 Optical Society of America