Xu Di, Coleto Andres Garcia, Moon Benjamin, Papa Jonathan C, Pomerantz Michael, Rolland Jannick P
Opt Express. 2020 Jul 6;28(14):19937-19953. doi: 10.1364/OE.394638.
Significant advances for optical systems in terms of both performance and packaging are enabled by freeform optical components. Yet, surface form metrology for freeform optics remains a challenge. We developed and investigated a point-cloud cascade optical coherence tomography (C-OCT) technique to address this metrology challenge. The mathematical framework for the working principle of C-OCT is presented. A novel detection scheme is developed to enable high-speed measurements. Experimental results validate the C-OCT technique with the prototype setup demonstrating single-point precision of ±26 nm (∼λ/24 at the He-Ne wavelength), paving the way towards full surface measurements on freeform optical components.
自由曲面光学元件在光学系统的性能和封装方面都取得了重大进展。然而，自由曲面光学器件的表面形状计量仍然是一个挑战。我们开发并研究了一种点云级联光学相干断层扫描（C-OCT）技术来应对这一计量挑战。本文介绍了C-OCT工作原理的数学框架。开发了一种新颖的检测方案以实现高速测量。实验结果验证了C-OCT技术，原型装置展示了±26 nm的单点精度（在氦氖波长下约为λ/24），为自由曲面光学元件的全表面测量铺平了道路。
