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像平面式干涉成像光谱仪的光程差(OPD)线性度与光谱及图像重建精度直接相关。分析了光程差产生原理,通过分别对单个像面的正离焦及负离焦部分光程差进行讨论,给出了像平面式干涉结构在单侧及双侧离焦模式下的光程差表达式,并对两者在不同波长满足奈奎斯特条件时的光程差及其非线性残差进行仿真,并通过实验验证。仿真结果表明:系统在两种工作模式下的光程差非线性残差均随像面夹角增加而增大,单侧离焦模式零级点两侧光程差不对称,且负离焦部分残差较小;双侧离焦模式零级点两侧光程差对称,但非线性残差大于前者。实验结果表明,当工作波长较短时(如紫外),单侧离焦模式负离焦部分在实际应用中可认为满足光程差线性分布关系。
Optical path difference (OPD) linearity like planar interferometric imaging spectrometers is directly related to spectral and image reconstruction accuracy. The principle of optical path difference generation is analyzed. By discussing the optical path difference of the positive and negative defocus of a single image plane respectively, the optical path length of the image plane interference structure in unilateral and bilateral defocus mode is given. Difference expression and the optical path difference and its nonlinear residual of the two under different Nyquist conditions are simulated and verified by experiments. The simulation results show that the system optical path length non-linear residual error increases with the increase of the image angle, the optical path difference of the zero-order point of the unilateral defocus mode is asymmetric, and the negative defocus Part of the residual smaller; bilateral defocus mode zero-order point on both sides of optical path length symmetry, but the nonlinear residual greater than the former. The experimental results show that when the working wavelength is short (such as UV), the unilateral defocus mode negative defocusing part can be considered in the practical application to meet the optical path difference linear distribution.