Wang Su-Yun, Huang Kai-Xuan, Guo Qin-Qin, Guo Hao-Wei, Tian Jian-Guo, Liu Zhi-Bo
The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and Teda Applied Physics Institute, Nankai University, Tianjin 300071, China.
The Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
J Phys Chem Lett. 2021 May 20;12(19):4755-4761. doi: 10.1021/acs.jpclett.1c01029. Epub 2021 May 13.
Black phosphorus (BP) is a typical two-dimensional (2D) layered material with strong in-plane anisotropy and large birefringence, making it possible to manipulate the light field with atomically controlled devices for various optoelectronic and photonic applications-for instance, atomic thickness waveplates. The twist angle in twisted black phosphorus (TBP) can be presented as a new tunable dimension to control BP's optical anisotropy. Here, we report a large and tunable optical rotation effect in TBP, the result of regulating the twist angle and BP thickness. To accurately study the optical rotation and the impact of the twist angle, we developed a new method to prepare TBP. A lab-made polarimeter microscope was used to visualize the optical rotation mapping of TBP. A large polarization-plane rotation (PORA) of 0.49° per atomic layer was observed from an air/BP/SiO/Si Fabry-Pérot cavity at 600 nm, an order of magnitude higher than the PORA of 0.05° per atomic layer reported earlier. For the same thickness, the PORA of TBP can be tuned from 0.48° to 7.75° based on the twist angle from 0° to 90°. Our work provides an efficient method to investigate the anisotropy of 2D materials and their heterojunctions. TBP could help us design novel optical and optoelectronic devices such as tunable nanoscale polarization controllers.
黑磷（BP）是一种典型的二维（2D）层状材料，具有很强的面内各向异性和大双折射，这使得利用原子级可控器件来操纵光场以用于各种光电和光子应用成为可能，例如原子厚度的波片。扭曲黑磷（TBP）中的扭曲角可作为控制BP光学各向异性的一个新的可调维度。在此，我们报道了TBP中一种大且可调的旋光效应，这是调节扭曲角和BP厚度的结果。为了精确研究旋光性以及扭曲角的影响，我们开发了一种制备TBP的新方法。使用实验室自制的旋光仪显微镜来可视化TBP的旋光映射。在600nm波长下，从空气/BP/SiO/Si法布里 - 珀罗腔中观察到每原子层有0.49°的大偏振面旋转（PORA），比之前报道的每原子层0.05°的PORA高一个数量级。对于相同厚度，基于0°到90°的扭曲角，TBP的PORA可从0.48°调至7.75°。我们的工作为研究二维材料及其异质结的各向异性提供了一种有效方法。TBP有助于我们设计新型光学和光电器件，如可调谐纳米级偏振控制器。
