Tunable optical topological transitions of plasmon polaritons in WTe_(2) van der Waals films  

作　　者：Yuangang Xie Chong Wang Fucong Fei Yuqi Li Qiaoxia Xing Shenyang Huang Yuchen Lei Jiasheng Zhang Lei Mu Yaomin Dai Fengqi Song Hugen Yan 

机构地区：[1]State Key Laboratory of Surface Physics,Key Laboratory of Micro and NanoPhotonic Structures(Ministry of Education),and Department of Physics,Fudan University,200433 Shanghai,China [2]Centre for Quantum Physics,Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE),School of Physics,Beijing Institute of Technology,100081 Beijing,China [3]Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systems,School of Physics,Beijing Institute of Technology,100081 Beijing,China [4]National Laboratory of Solid State Microstructures,Collaborative Innovation Center of Advanced Microstructures,and College of Physics,Nanjing University,210093 Nanjing,China [5]Atom Manufacturing Institute(AMI),211805 Nanjing,China [6]Center for Superconducting Physics and Materials,National Laboratory of Solid State Microstructures and Department of Physics,Nanjing University,211805 Nanjing,China

出　　处：《Light(Science & Applications)》2023年第9期1807-1817,共11页光（科学与应用)（英文版）

基　　金：H.Y.is grateful to the financial support from the National Key Research and Development Program of China(Grant Nos.2022YFA1404700 and 2021YFA1400100);the National Natural Science Foundation of China(Grant No.12074085);the Natural Science Foundation of Shanghai(Grant No.23XD1400200);C.W.is grateful to the financial support from the National Natural Science Foundation of China(Grant Nos.12274030,11704075);the National Key Research and Development Program of China(Grant No.2022YFA1403400);F.S.acknowledges the financial support from the National Key Research and Development Program of China(Grant No.2017YFA0303203);the National Natural Science Foundation of China(Grant Nos.92161201,12025404,11904165,and 12274208);the Natural Science Foundation of Jiangsu Province(Grant No.BK20190286);S.H.is grateful to the financial support from the China Postdoctoral Science Foundation(Grant No.2020TQ0078);Part of the experimental work was carried out in Fudan Nanofabrication Lab.

摘　　要：Naturally existing in-plane hyperbolic polaritons and the associated optical topological transitions,which avoid the nano-structuring to achieve hyperbolicity,can outperform their counterparts in artificial metasurfaces.Such plasmon polaritons are rare,but experimentally revealed recently in WTe_(2)van der Waals thin films.Different from phonon polaritons,hyperbolic plasmon polaritons originate from the interplay of free carrier Drude response and interband transitions,which promise good intrinsic tunability.However,tunable in-plane hyperbolic plasmon polariton and its optical topological transition of the isofrequency contours to the elliptic topology in a natural material have not been realized.Here we demonstrate the tuning of the optical topological transition through Mo doping and temperature.The optical topological transition energy is tuned over a wide range,with frequencies ranging from 429 cm^(−1)(23.3 microns)for pure WTe_(2)to 270 cm^(−1)(37.0 microns)at the 50%Mo-doping level at 10 K.Moreover,the temperature-induced blueshift of the optical topological transition energy is also revealed,enabling active and reversible tuning.Surprisingly,the localized surface plasmon resonance in skew ribbons shows unusual polarization dependence,accurately manifesting its topology,which renders a reliable means to track the topology with far-field techniques.Our results open an avenue for reconfigurable photonic devices capable of plasmon polariton steering,such as canaling,focusing,and routing,and pave the way for low-symmetry plasmonic nanophotonics based on anisotropic natural materials.

关 键 词：TOPOLOGICAL TRANSITIONS POLAR 

分 类 号：O17[理学—数学]