Detection of terahertz radiation with low-temperature-grown GaAs-based photoconductive antenna using 1.55 μm probe

Abstract

THz radiation is detected by a low-temperature-grown GaAs (LT-GaAs) photoconductive antenna probed with a 1.55 μm probe laser. The detection efficiency is found to be approximately 10% of that obtained with a 780 nm probe. From the nonquadratic dependence of photoconductivity on laser intensity, two-step photoabsorption mediated by midgap states in LT-GaAs is suggested, instead of the two-photon absorption, as the primary process for the photoconductivity. © 2000 American Institute of Physics.