环境适应性中红外宽带减反射元件的研制

Fabrication of Environmentally Adaptive Mid-Infrared Broadband Antireflection Components

通过微结构结合镀膜的方法成功设计和制备了中红外宽带减反射元件。首先,利用FDTD Solutions软件,模拟了微结构周期、占空比、高度以及膜层厚度对所需波段透射率的影响规律,得到较好增透效果的微结构和膜层结构参数;根据设计参数,采用激光干涉曝光和反应离子束刻蚀技术在蓝宝石表面制备出相应微结构,然后在其表面镀制相应厚度的SiO2膜。测试结果表明:仅有单面微结构的蓝宝石元件在1.5~4μm波段的平均透射率达到92.3%,具有复合结构的蓝宝石元件在该波段的平均透射率高达98.7%,相对双面抛光蓝宝石样品透射率提升11.0%左右,实现了蓝宝石表面的宽带增透;对具有复合结构的蓝宝石元件进行了湿度验证和高低温循环实验,实验前后透射率曲线无明显变化,且无明显水吸收,说明该元件具有很好的环境适用性。

Infrared broadband antireflection components were successfully fabricated using a microstructure approach combined with a coating method. First, the influence of period, filling factor, height, and film thickness on the required band transmittance was simulated using FDTD Solutions software. As such, the microstructure and film parameters corresponding to good antireflection were obtained. Then, according to these parameters, a parabolic cone microstructure was prepared onto the surface of a sapphire through laser interference lithography combined with reactive ion etching technology. Finally, a SiO2 film layer was coated onto the surface of the microstructure. Test results show that the average transmittance of samples with single-sided microstructure and composite structure at 1.5--4 μm were 92.3% and 98.7%, respectively. Therefore, the transmittance increased by 11.0% compared with double-sided polished sapphire samples. Infrared broadband antireflection of the sapphire was obtained. Finally, a high-and-low temperature cycle and humidity experiment was conducted on sapphire element with composite structure. This experiment shows that the change in transmittance was not obvious and without obvious water absorption, indicating that the component has environmental durability.