Knöckl Ernst, Bernard Alexandre, Holleitner Alexander, Kastl Christoph
Walter Schottky Institute and Physics Department, Technical University of Munich, 85748, Garching, Germany.
Munich Center For Quantum Science and Technology (MCQST), Schellingstr. 4, 80799, München, Germany.
Sci Rep. 2025 May 2;15(1):15344. doi: 10.1038/s41598-025-96894-8.
Polarized optical contrast spectroscopy is a simple and non-destructive approach to characterize the crystalline anisotropy and orientation of two-dimensional materials. Here, we develop a 3D-printed motorized polarization module, which is compatible with typical microscope platforms and enables to perform broadband polarization-resolved reflectance spectroscopy. As proof of principle, we investigate the in-plane birefringence of exfoliated [Formula: see text] thin films and few-layer [Formula: see text] crystals. We compare the measured spectra to a model based on a transfer matrix formalism. Compared to other polarization sensitive approaches, such as Raman or second harmonic generation spectroscopy, optical contrast measurements require orders of magnitude less excitation power densities, which is particularly advantageous to avoid degradation of delicate van der Waals layers.
偏振光学对比度光谱法是一种简单且无损的方法，用于表征二维材料的晶体各向异性和取向。在此，我们开发了一种3D打印的电动偏振模块，它与典型的显微镜平台兼容，并能够进行宽带偏振分辨反射光谱测量。作为原理验证，我们研究了剥离的[化学式：见原文]薄膜和少层[化学式：见原文]晶体的面内双折射。我们将测量光谱与基于转移矩阵形式的模型进行比较。与其他偏振敏感方法（如拉曼光谱或二次谐波产生光谱）相比，光学对比度测量所需的激发功率密度要低几个数量级，这对于避免脆弱的范德华层降解特别有利。
