2 μm波段激光器在环境探测、测风雷达、生物组织切割、光电对抗等领域都有重要的应用价值和前景。而此波段的薄膜通常采用折射率较高的硫化物、砷化物等软膜材料来制备, 为了提升该波段薄膜的损伤性能, 采用折射率相对较低但能带隙更宽的氧化物材料来制备。利用傅里叶红外光谱仪和弱吸收测试仪分析表征了薄膜中OH基含量的多少和薄膜整体吸收的大小, 通过优化工艺, 成功制备出了满足2 020 nm的铥(Tm)激光器使用要求的多层介质薄膜。利用微分干涉显微镜观察了经过激光损伤测试薄膜的损伤形貌, 结合薄膜中电场分布和应力测试结果, 分析探讨了此薄膜的损伤机理, 提出进一步优化薄膜损伤特性的方案。

Infrared lasers at 2 μm wavelength have great application value and good prospects in the environmental detection, wind-measuring radar, tissue ablation as well as optoelectronic countermeasure. The films at 2 μm wavelength were often prepared by sulphide, arsenide and other soft material which have high refractive index. In order to promote the damage performance of these films, the oxide material was used whose refractive index was relatively lower but the bandgap was wider to prepare the film. The content of OH and the absorption of the film were characterized by using Fourier infrared spectrometer and the weak absorption tester. By optimizing the fabrication process, the multilayers dielectric thin films which satisfy the requirements of the 2 020 nm Tm laser were successfully prepared. The damage morphologies of the films after the laser damage testing were observed by the differential interference microscope, combining with the electric field distribution and the stress in the film, the damage mechanism of the films were analyzed and further optimization method of damage character was put forward.