利用复振幅设计10.6μm偏振分光膜

Using complex-amplitude to design PBS film of 10.6 μm

为了得到10.6μm处偏振分光膜,采用薄膜光学的复振幅理论,利用受抑全内反射原理对传统的偏振分光膜的设计思想进行了改进,即通过抑制复振幅反射率为0,得到各膜层厚度。以10.6μm光波入射,仿真了不同入射角条件下的膜层厚度关系曲线,通过对曲线簇交叉点的取值,构建了偏振分光膜系的初始结构,通过Macleod优化设计了10.6μm红外偏振分光膜,所设计的偏振分光膜在10.6μm处,p偏振光透射率达到了92%,s偏振光反射率达到了93%,入射角范围是65～75°(玻璃中),反射偏振光消光比102～103。结果表明:此方法在偏振分光膜设计中有重要的应用价值。

In order to get a laser polarizing beam-splitting （PBS） film of 10.6μm,the conventional PBS film＇s design method was modified by using complex-amplitude theory of film optics based on the principle of frustrated total internal reflection （FTIR）,where the reflectivity of complex-amplitude was suppressed to zero, and every film thickness was obtained. The relationship curves of film thickness with different incidence angles were simulated at 10.6 μm incident wavelength. By the crosspoint values of the simulated curves cluster, the original structure of film layers of polarizing beam-splitting film was established. The infrared beam-splitting film at 10.6μm wavelength was optimized by the Macleod software. The transmission ratio of the designed p polarizing beam-splitting film was about 92%, and the reflectivity of the s polarizing beamsplitting film was about 93%. The range of incidence angle was from 65°to 75° .The extinction ratio of reflective polarizing beam-splitting film was from 10^2 to 10^3. The above result shows that the new method has important applications value on the design of polarizing beam-splitting film.