Hu Yong, Baggio Mariangela, Dabironezare Shahab, Tamminen Aleksi, Toy Brandon, Ala-Laurinaho Juha, Brown Elliott, Llombart Nuria, Deng Sophie X, Wallace Vincent, Taylor Zachary D
Department of Bioengineering, University of California, Los Angeles, CA 90095 USA.
Department of Electronics and Nanoengineering, Aalto University, Espoo, FI-02150, Finland.
IEEE Trans Terahertz Sci Technol. 2022 Mar;12(2):151-164. doi: 10.1109/tthz.2021.3140199. Epub 2022 Jan 4.
A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing 5 off-axis parabolic mirrors, a thin film beam splitter, and 2-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off.
本文提出了一种用于毫米波角膜反射测量在线对准验证的系统概念。该系统利用光束扫描在650GHz下生成角膜的仅幅度反射率图，并将这些图像与预先计算/测量的模板图进行比较，以确认/拒绝是否有足够的对准。设计、模拟并使用几何光学和物理光学评估了一个利用5个离轴抛物面镜、一个薄膜分束器和两轴振镜的系统。模拟结果为一个用参考反射器进行测试的演示系统的构建提供了依据。使用对齐模板和分布在0.5mm×0.5mm×0.5mm网格上的26个未对齐位置计算的相似性指标表明，在26个位置中的23个位置具有足够的未对准检测灵敏度。结果表明，由于光束畸变和光束离散导致耦合效率的扰动，使用0.462mm波长的辐射可以实现约0.5mm的位置精度。
