干涉仪仪器传递函数噪声容限分析与优化

Analysis and optimization of noise tolerance for interferometer instrument transfer function

在高精度平面干涉仪系统评价标准中,仪器传递函数(Instrument Transfer Function,ITF)已经逐渐成为干涉仪性能的重要评价指标,它准确地反映了光学系统对于测量形貌不同空间频率的分辨能力。然而,ITF测试过程中的实验环境要求较为严格,干涉仪系统噪声会导致测试结果产生较大失真。为了能够准确表征干涉仪系统的性能,通过仿真分析与实际实验结合的方式,将仿真干涉图引入不同量级的高斯随机噪声,探究了噪声对于ITF测试结果的影响,提出测试误差的评价指标ITF_(RMS)值,分析了干涉仪系统的噪声容限,依据评价指标提出了几种不同的ITF测试优化方法,并搭建实验系统进行分析验证。实验结果表明,在未优化的ITF测试流程中,所搭建的干涉仪系统ITF测试的ITF_(RMS)值为0.1112,而优化后同样噪声量级的干涉仪系统所得ITF_(RMS)值则分别降至0.0693,0.0367,0.0579。此结果证明了优化方案的可行性,该方案能有效抑制干涉仪系统ITF测试过程中的噪声干扰影响。

In the evaluation of high-precision flat interferometer systems,the Instrument Transfer Function(ITF)has become an essential index for assessing interferometer performance.It accurately characterizes the resolution capability of optical systems in measuring profiles at different spatial frequencies.However,strict experimental environment requirements and interference system noise can significantly distort ITF test results.To accurately characterize interferometer performance,this paper combines simulation analysis with practical experiments,introducing simulated interferograms into varying levels of Gaussian random noise.We explore the impact of noise on ITF test results,propose the ITF_(RMS) value as an evaluation index for measurement error,and analyze the noise tolerance of the interferometer system.Several ITF test optimization methods are presented based on this evaluation index.An experimental system is built for analysis and validation.The final results indicate that in the unoptimized ITF testing process,the ITF_(RMS) value of the interferometer system is 0.1112.After optimization,with the same noise level,ITF_(RMS) values reduce to 0.0693,0.0367,and 0.0579,respectively.These results demonstrate the feasibility of the proposed optimization scheme,effectively suppressing noise interference during ITF testing of the interferometer system.