熔石英激光诱导损伤的太赫兹检测

Terahertz Inspection of Laser-Induced Damage of Fused Silica

基于透射式太赫兹时域光谱系统,对熔石英在不同能量激光诱导损伤与未损伤区域进行检测,获得其时域光谱及0.8-1.25 THz频谱图,分析了峰峰值、振幅、透射谱、折射率及吸收系数,结果表明.损伤区域与未损伤区域相比,其峰峰值、振幅、透射谱、折射率明显减小,且随着激光诱导能量的增加,损伤面积增大,这些参数也逐渐减小;吸收系数呈相反的变化趋势。因此,可利用熔石英太赫兹波段光学特性的变化,对其激光诱导损伤和损伤程度进行识别,为太赫兹时域光谱技术在激光诱导损伤识别分析中的应用做良好的铺垫。

In this study,the undamaged and damaged areas in fused silica induced by laser with different energies were tested with the transmission terahertz time-domain spectral system.The time domain signal and frequency spectra of 0.8-1. 25THz are obtained.The peak-to-peak value,amplitude,transmission spectrum,refractive index,and absorbance are analyzed.The results show that the peak-to-peak value,amplitude,transmission spectrum,and refractive index of the damaged area are obviously reduced compared with those of the undamaged area,and with the increase of laser energy and the enlargement of damaged area,these parameters gradually decrease.In contrast,the absorbance exhibits an opposite change.Therefore,the variation in the optical properties of fused silica in the terahertz wave band could be applied to distinguish the damages and analyze the degree of damage,which provides a good basis for applying the terahertz time domain spectral technique to the identification and analysis of laser-induced damage.