Qin Jun, Deng Longjiang, Kang Tongtong, Nie Lixia, Feng Huayu, Wang Huili, Yang Run, Liang Xiao, Tang Tingting, Shen Jian, Li Chaoyang, Wang Hanbin, Luo Yi, Armelles Gaspar, Bi Lei
National Engineering Research Center of Electromagnetic Radiation Control Materials, University of Electronic Science and Technology of China, Chengdu 610054, China.
Instituto de Micro y Nanotecnologı́a (IMN-CNM), CSIC (CEI UAM+CSIC), Isaac Newton, 8, Tres Cantos 28760, Madrid, Spain.
ACS Nano. 2020 Mar 24;14(3):2808-2816. doi: 10.1021/acsnano.9b05062. Epub 2020 Feb 21.
Chiral nanophotonic devices are promising candidates for chiral molecule sensing, polarization of diverse nanophotonics, and display technologies. Active chiral nanophotonic devices, where the optical chirality can be controlled by an external stimulus has triggered great research interest. However, efficient modulation of the optical chirality has been challenging. Here, we demonstrate switching of the extrinsic chirality by applied magnetic fields in a magnetoplasmonic metasurface device based on a magneto-optical oxide material, CeYFeO (Ce:YIG). Due to the low optical loss and strong magneto-optical effect of Ce:YIG, we experimentally demonstrated giant and continuous far-field circular dichroism (CD) modulation by applied magnetic fields from -0.6 ± 0.2° to +1.9 ± 0.1° at 950 nm wavelength under glancing incident conditions. The far-field CD modulation is due to both magneto-optical circular dichroism and near-field modulation of the superchiral fields by applied magnetic fields. Finally, we demonstrate magnetic-field-tunable chiral imaging in millimeter-scale magnetoplasmonic metasurfaces fabricated using self-assembly.
手性纳米光子器件是用于手性分子传感、各种纳米光子学的偏振以及显示技术的有前途的候选者。有源手性纳米光子器件，其光学手性可通过外部刺激进行控制，已引发了极大的研究兴趣。然而，光学手性的有效调制一直具有挑战性。在此，我们展示了在基于磁光氧化物材料CeYFeO（铈铁石榴石）的磁等离子体超表面器件中，通过施加磁场来切换外在手性。由于Ce:YIG的低光学损耗和强磁光效应，我们通过实验证明了在掠入射条件下，在950nm波长处，施加磁场可实现从-0.6±0.2°到+1.9±0.1°的巨大且连续的远场圆二色性（CD）调制。远场CD调制是由于磁光圆二色性以及施加磁场对超手性场的近场调制共同作用的结果。最后，我们展示了在使用自组装制造的毫米级磁等离子体超表面中的磁场可调手性成像。
