THz-EO sampling using GaAs in Cherenkov-phase-matching scheme at 1.55-μm sampling wavelength
Abstract
In a previous work, we proposed and demonstrated electro-optic (EO) sampling detection of pulsed terahertz (THz) radiation based on the non-collinear Cherenkov phase-matching with a Si-prism coupled LiNbO3 (Si/LN) crystal at 1.55 μm sampling wavelength in a balanced detection setup. However, this EO sampling scheme is complex and requires compensation for birefringence. We also reported a new electro-optic sampling scheme, that is, the “heterodyne EO sampling.” In this heterodyne scheme, compensation for birefringence is not necessary but the signal-to-noise ratio (SNR) is bad compared to balanced detection. In this work, we propose and demonstrate Cherenkov phase-matched EO sampling of THz radiation at 1.55-μm wavelength by using GaAs in a balanced detection setup. This setup is simpler and does not require compensation for birefringence. Experimental results also show better SNR.