Fabrication and applications of orientation-patterned gallium arsenide for mid-infrared generation

Nonlinear optical materials play a key role in the development of coherent sources of radiation, by frequency conversion of light from other light sources, e. g. diode, solid-state, and fiber lasers, into spectral ranges where few lasers exist or perform poorly. Based on the principle of the quasi-phase matching, the design and fabrication of orientation-patterned Gallium Arsenide crystals (OP-GaAs) has recently led to demonstrations of second harmonic generation, optical parametric generation, amplification and oscillation from 1 to 12 mu m. The most efficient fabrication route for these crystals relies on the use of the near-equilibrium growth process HVPE (Hydride Vapour Phase Epitaxy), by orientation-selective regrowth on OP-GaAs template wafers with a thickness suited to bulk nonlinear optics. This work deals with recent characterizations based on optical experiments and cathodoluminescence measurements, targeting the identification of the main defects, their spatial distribution, and their relation to the optical propagation losses. Latest improvements of the HVPE growth step have enabled to reach an unprecedented level of losses, below 0.016 cm(-1), and a large range of available QPM periods and thickness of structures. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim