Aperiodic Grating Design Methods Employed For Idler-Efficiency Enhanced Beam Generation in Orientation-Patterned GaAs

In this paper, we compare the theoretical performance of two design methods that allow simultaneous phase matching of two arbitrary chi((2)) processes along with the capability of adjusting their relative strength. The crystal of these 1-D aperiodic gratings is chosen to be the orientation-patterned gallium arsenide (OP-GaAs), which has been recently used in several devices for high power infrared beam generation. These single gratings placed in an optical parametric oscillator (OPO) or an optical parametric generator (OPG) can simultaneously phase match two optical parametric amplification (OPA) processes, OPA-1 and OPA-2, for converting the 2.1-mu m pump laser radiation into the long-wave infrared (8-12 mu m) in an idler-efficiency enhanced scheme.