A study on narrow-band thz (Terahertz) source with adjustable center frequency based on optical rectification

Abstract

The center frequency of the narrow-band THz wave is always unstable with the optical rectification methods. Therefore, the high-phase stable time-delay generator Etalon and the parallel grating pair compressor with the self-adaptive optical path compensation function are designed according to the principle that two lasers in different paths will result in specific relative time delay; with LiNbO3 waveguide sample as the optical rectification crystal, the quasi-multi-cycle narrow-band THz wave generating platform is set up based on the two chirp-delay schemes (one Compressor in the pump branch and another Compressor in the probe branch) Both schemes can generate narrow-band THz waves with adjustable center frequency from 0.25~1.2THz. The bandwidth is 100GHz, with good frequency stability.