基于多向倾斜载频的复杂面形全场三维形貌非零位新型点衍射干涉测量术研究

Complex Surface Optical Elements (CSOE) could eliminate more aberrations and simplify the whole system. So CSOEs are also viewed as the next generation precision optical components. However, it is more difficult to measuring a CSOE because of its more complex parameters, which has been a hot research topic. Usually, interferometry is an effective method to measure 3D profile of surface. But the precision and aperture of traditional interferometry are limited by CSOEs with high surface gradients. Thus, a novel non-null point-diffraction interferometry based on multi-directions inclined carrier is proposed in this project. It has a point diffraction array (PDA) based on point-diffraction interferometry, which are made up of fibers. The PDA generates multi-directions inclined carrier to compensate the surface local gradients. Therefore, it solve the problem of a traditional interferometry failure for CSOEs with high surface gradients. Meanwhile it eliminates aberrations caused by lens group in the traditional interferometric system and makes it impossible to measure larger optical elements. As multi-directions inclined carrier are being adopted, the interferometric system is no longer satisfying for null interferometer. Thus many sub-topics about the non-null point-diffraction interferometry based on multi-directions inclined carrier will be researched theoretically and experimentally: mathematical model of non-null interferometer based on the PDA; mathematical model between point diffraction array and the shape function of the tested surface; reconstruction algorithm of tested surfaces in proposed interferometer; interferometric system error calibration method. Finally, a new metrology for testing 3D profile of complex surface is established by our novel methods.

复杂面形光学元件优化像差的同时简化系统结构，是新一代光学元件。面形的复杂度使其全场三维形貌检测成为光学领域研究热点。干涉术是三维面形测量的有效手段，但复杂面形的大梯度变化使得传统干涉的测量精度和口径受到限制。针对该问题，本项目创新的提出了基于多向倾斜载频的新型点衍射干涉术。该方法在点衍射干涉基础上利用光纤阵列构成点衍射阵，从而产生多向倾斜载频的波面补偿被检面的表面梯度，解决复杂面形的大梯度变化使得传统干涉失效问题，同时点衍射波面代替传统干涉镜头组能避免引入大量波像差及镜头组的口径限制使得无法测量大口径元件的问题。由于采用多向倾斜载频，点衍射干涉不再满足零位干涉条件，因此需要研究非零位条件下点衍射干涉数理新机制，包括：非零位型空间点衍射阵干涉数理模型；点衍射阵的排布与被检面形分布之间数学模型；多向倾斜载频点衍射干涉相位重构面形算法；误差标定方法。最终建立复杂面形全场三维纳米级测量精度新方法。

复杂曲面光学元件能够在提高光学系统成像质量或进行特殊光场调制的同时，使系统结构轻量化和微型化，是光电系统中的理想元件。该类元件在空间光学、精密成像系统等领域有非常重要的应用，其测量技术的研究是光学元件测量领域的前沿技术问题。目前在光学检测研究领域，还没有成熟可靠的方法能完全实现其面形的高精度、高效率、通用化测量。针对复杂曲面面形高精度测量的难题，本项目研究了基于多向倾斜载频的非零位点衍射干涉检测技术，建立了适应光学复杂曲面检测的倾斜载频非零位点衍射干涉数理模型，提出了点衍射阵的排布与被检面形之间的数学模型及动态生成点衍射阵的规划方法；结合深度学习攻克基于倾斜载频的非零位点衍射干涉相位重构面形的算法等关键技术。设计并研制了基于多向倾斜载频的非零位点衍射干涉复杂曲面面形检测原理性实验系统，对项目的模型及算法进行了验证试验，建立了用于复杂曲面面形检测的倾斜载频非零位点衍射干涉理论体系。所研制的基于倾斜载频的非零位点衍射干涉复杂曲面面形检测系统，对复杂曲面面形的测量不确定度优于λ/37（RMS值），达到国际先进水平。本项目成果可以为各类光学复杂曲面加工和应用提供准确的测试手段和方法，大大降低复杂曲面的加工成本和时间，解决我国在光学复杂曲面加工上的难题，为光学复杂曲面的国产化以及广泛应用奠定工业基础，从而为我国光电产品的革新提供优质元件，创造更多的经济效益。同时也可以应用于船舶、电子、航空、航天等国防与民用行业的企业、研究所与高校，作为光学元件的产品生产、科学研究的测量方法。项目发表学术论文7篇，SCI收录5篇，EI收录2篇，申请国家发明专利6项，已授权4项。