Analysis of broadband second harmonic generation in a trapezoidal isotropic semiconductor slab with an elliptical upper surface using total internal reflection quasi phase matching.

This paper analytically describes the concept of an extremely wide broadband frequency converter with appreciable conversion efficiency in a trapezoidal isotropic semiconductor slab with an elliptical upper surface. The frequency conversion scheme corresponds to Second Harmonic Generation (SHG) using Total Internal Reflection Quasi Phase Matching (TIR-QPM). The simulation has been performed using Gallium Arsenide (GaAs) as the non-linear material, in the fundamental wavelength range of 6.8–10.8 μm, considering ppp polarization configuration. Optimized simulation results, after considering reflection and absorption losses, show an extremely wide 3 dB bandwidth of 770 nm in a 40 mm slab with a conversion efficiency of 1.088%.