Hemispherical semi-insulating GaAs double-frequency absorption photodetector operating at 1.3 μm wavelength

The hemispherical semi-insulating GaAs photodetector operating at 1.3 mu m is presented. The GaAs hemisphere was used both as a detector and a solid immersion lens to improve the responsivity. The physical mechanism of the detector is attributed to double-frequency absorption (DFA) confirmed by the measured photocurrent quadratically dependent on the incident optical power and nonlinearly dependent on the bias and by the relationship between the photocurrent and the azimuth in agreement with the anisotropy of DFA in GaAs single crystal. (c) 2007 American Institute of Physics.