建立了表面热透镜技术测量光学薄膜微弱吸收的实验装置,对10.6μm CO₂激光辐照下镀制在Ge基底上的不同厚度的单层ZnS,YbF₃薄膜,以及镀制在Ge基底上不同膜系的(YbF₃/ ZnSe)多层分光膜的弱吸收进行了测量,并对实验结果作了分析和讨论.实验结果表明,利用本实验系统已测得的待测样品的最低吸收为2.87×10^-4,测量系统的灵敏度为10^-5.

The absorption of optical thin film coatings is one of the main factors that limit the development of high power lasers. It is necessary to measure the absorption of the optical thin film coatings precisely, fast and in real-time. The experimental setup for measuring the weak absorption of the optical thin films has been built using the surface thermal lensing technique. The weak absorption of different optical thin films, including the single-layer ZnS and YbF₃ dielectric thin films with different thickness, as well as the different multi-layer thin films (YbF₃/ ZnS) deposited on Ge substrate, irradiated by 10.6μm CO₂ laser has been measured. The experimental results show that the lowest absorption measured by the experimental system is 2.87×10^-4 and the sensitivity of the experimental system is about 10^-5.