飞秒激光作用ZnSe晶体产生和探测THz辐射的实验

THz-Wave Generation and Detection from ZnSe Crystal Induced by a Femtosecond Laser

实验研究了ZnSe单晶的光学整流THz产生,借助电光取样技术得到THz脉冲的时域波形和FFT频谱分布,观察到约113fs的THz辐射场分布,及相应约5·8THz的频谱分布,辐射峰位于3THz左右.对比研究了不同表面的ZnSe晶体的THz辐射峰值强度随激发光功率的变化,通过轻微烧蚀模型定性解释了高激发功率下THz信号的饱和机制.

We experimentally study THz generation and detection in 〈 111〉 ZnSe samples using optical rectification and electro-optic sampling.A THz radiation pulse with a width of 113fs （full width at half maximum）,results in a wideband THz spectrum near 5. 8THz with a peak signal at 3THz. We also examine the dependence of the peak THz electric field on optica pump power. The generated peak electric field increase linearly with increasing optical pump power in the ZnSe sample with a clean surface, while for the sample with a carbon-sprinkled surface, the peak field exhibits a slow saturation behavior at powers greater than 250mW. It seems that the damages surface decreases the optical rectification efficiency.