Chen Zehong, Shi Zhonghong, Zhang Wenbo, Li Zixian, Zhou Zhang-Kai
State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
Nanophotonics. 2022 Mar 1;11(7):1379-1387. doi: 10.1515/nanoph-2021-0789. eCollection 2022 Mar.
Nonlinear nanophotonic devices have brought about great advances in the fields of nano-optics, quantum science, biomedical engineering, etc. However, in order to push these nanophotonic devices out of laboratory, it is still highly necessary to improve their efficiency. Since obtaining novel nanomaterials with large nonlinearity is of crucial importance for improving the efficiency of nonlinear nanodevices, we propose the two-dimensional (2D) perovskites. Different from most previous studies which focused on the 2D perovskites in large scale (such as the bulk materials or the thick flakes), herein we studied the 2D perovskites nanosheets with thickness of ∼50 nm. The high-order nonlinear processes including multi-photon photoluminescence and third-harmonic generation (THG) have been systematically investigated, and it is found the THG process can have a high conversion efficiency up to ∼8 × 10. Also, it is observed that the nonlinear responses of 2D perovskites have large optical anisotropy, i.e., the polarization ratio for the incident polarization dependence of nonlinear response can be as high as ∼0.99, which is an impressive record in the perovskite systems. Our findings reveal the properties of high efficiency and huge optical anisotropy in the nonlinear processes of 2D perovskite nanosheets, shedding light on the design of advanced integrated nonlinear nanodevices in future.
非线性纳米光子器件在纳米光学、量子科学、生物医学工程等领域取得了巨大进展。然而，为了将这些纳米光子器件推向实验室之外，提高其效率仍然非常必要。由于获得具有大非线性的新型纳米材料对于提高非线性纳米器件的效率至关重要，我们提出了二维（2D）钙钛矿。与以往大多数专注于大规模二维钙钛矿（如块状材料或厚薄片）的研究不同，在此我们研究了厚度约为50纳米的二维钙钛矿纳米片。对包括多光子光致发光和三次谐波产生（THG）在内的高阶非线性过程进行了系统研究，发现THG过程可以具有高达约8×10的高转换效率。此外，观察到二维钙钛矿的非线性响应具有很大的光学各向异性，即非线性响应的入射偏振依赖性的偏振比可高达约0.99，这在钙钛矿体系中是一个令人印象深刻的记录。我们的研究结果揭示了二维钙钛矿纳米片非线性过程中的高效率和巨大光学各向异性特性，为未来先进集成非线性纳米器件的设计提供了启示。
