硒化锌基底3～12μm渐变折射率红外增透膜的设计

The Gradient-index Thin Film Design of Infrared Films on ZnSe Substrate for 3~12μm

叙述了傅里叶合成方法的原理和该方法用于ZnSe基底3～12μm红外增透膜的设计。通过反傅里叶变换期望的光谱特性曲线得到渐变折射率膜层。用薄膜特征矩阵的方法计算细分成很薄的多层均匀膜层的光谱透过率曲线,构造了新的Q函数和用逐次近似的方法修正膜层的折射率轮廓图,能有效地减小与期望透射率曲线的偏差。再给膜层加上五次方多项式匹配层与空气和基底两侧界面相匹配。所得渐变折射率增透膜在设计波段平均透射率达到95%。

In the paper, Fourier-transform method was introduce and was used for the design of infrared films on ZnSe substrate for 3 ～ 12μm. The refractive-index profile of Gradient-index film was obtained by inverse Fourier transformation of the desired spectral transmission curve and the corresponding spectral transmission curve was evaluated by using conventional matrix multiplication. The curve was refined through successive approximation and restructured new Q function to reduce the deviations from desired transmission curve. The quintic matching layers were overlayed at both interface of air and substrate. The average transmission of the Gradient-index film in the design wavelength range is 95%.