Applications of parametric light sources based on quasi-phase-matched materials to chemical sensing

Summary form only given. The emergence of practical quasi-phase-matched nonlinear materials has allowed development of infrared (IR) light sources that were not previously possible. Examples include compact optical parametric oscillators (OPOs) and simple single-pass devices (optical parametric generators, difference-frequency lasers). These developments are significant for IR chemical sensing, where there has long been a lack of available sources suitable for many applications. An "ideal" IR laser for chemical detection would tune over a significant portion of the fundamental absorption region (/spl sim/400-3500 cm/sup -1/) while exhibiting narrow (<0.1 cm/sup -1/) output bandwidth, and sufficient power in a compact format. Traditional IR sources (e.g., Pb-salt diodes, CO/sub 2/ lasers, and birefringently-phase-matched nonlinear devices) fall short of these specifications. By virtue of their high gain, broad phase-matching bandwidth, and noncryogenic operation, QPM devices offer great promise to ultimately reach this ideal. We summarize the performance of QPM-based chemical sensors developed at Sandia.