基于非线性光学差频及参量效应的太赫兹源

Terahertz Wave Sources Based on Difference Frequency Generation and Optical Parametric Processes

基于非线性光学技术的THz源具有其独特的性能和优点,将基于非线性光学差频原理和光学参量效应,从理论上研究并分析THz波与抽运光、闲频光及相位匹配角之间的关系,得到THz波输出的条件和范围,并设计出宽波段连续可调的THz源。以调QNd∶YAG激光器和光学参量振荡器(OPO)作为抽运源,以GaSe和MgO∶LiNbO3晶体作为差频非线性晶体,根据相位匹配理论及光学参量效应,搭建两套THz波产生系统。其中,基于光学参量效应的THz辐射源有效地产生出THz信号。

The THz source based on the nonlinear optical effects possesses the special properties and advantages. A theoretical study has been made for the generation of widely tunable narrow-band THz wave based on the process of the difference frequency generation （DFG） and the stimulated polariton scattering in a GaSe crystal and a MgO doped LiNbO3 crystal, respectively. The relations among the THz wave, pump wave, idler wave and phase-matching angle are analysed. The condition and range of THz radiation generation are given. ANd： YAG laser and an optical parametric oscillator （OPO） have been used to provide the pump and idler beams. A THz radiation generation system is built under collinear phase-matching conditions. A THz-wave parametric generator （TPG） is developed, and the TPG emits THz efficiently.