表面出射太赫兹波参量振荡器的设计与增强输出

Optical design and enhanced output of a surface-emitted THz-wave parametric oscillator

摘要: 利用一台多纵模调Q Nd：YAG激光器泵浦的浅表垂直发射太赫兹波参量振荡器参量产生了高功率可调谐太赫兹波辐射。推导了非共线相位匹配条件下的有效参量增益长度以优化太赫兹波参量振荡器参数。实验测得太赫兹波的调谐范围为0.77~2.83 THz。当泵浦功率密度为222.3 MW/cm2时，在1.78 THz处太赫兹波的最大输出能量为347.8 nJ/pulse，对应的能量转化效率为3.9110-6。太赫兹波在垂直方向上的远场发散角为0.020 4 rad，在水平方向上为0.006 8 rad。

Abstract: High-power tunable terahertz wave(THz-wave) radiation was parametrically generated via a surface-emitted THz-wave parametric oscillator(TPO) pumped by a multi-longitudinal-mode Q-switched Nd:YAG laser. The effective parametric gain length under the condition of noncollinear phase matching was calculated to optimize the parameters of TPO. The THz-wave radiation from 0.77 to 2.83 THz was obtained. The maximum THz-wave output is 347.8 nJ/pulse at 1.78 THz when the pump power density is 222.3 MW/cm2, corresponding to the energy conversion efficiency of 3.9110-6. The far-field divergence angle of THz-wave radiation is 0.020 4 rad at vertical direction and 0.006 8 rad at horizontal direction.