Absorption processes of the first and second order in GaAs in the THz-IR range

Abstract

Absorption of THz radiation in gallium arsenide (GaAs) substrates of photoconductive antennas determines the generation and detection efficiency, as well as the dynamic and frequency ranges, of THz spectrometers. Based on the THz and IR experimental data and their calculations using classical dispersion models, absorption processes in the THz–IR regions were analyzed, and broadband data on the temperature evolution of the optical parameters of GaAs substrates were obtained. The contribution of anharmonicity effects in the formation of the dielectric response function of GaAs in the THz range is demonstrated.