Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi2Te3  

作　　者：Haihui Zhao Xinhou Chen Chen Ouyang Hangtian Wang Deyin Kong Peidi Yang Baolong Zhang Chun Wang Gaoshuai Wei Tianxiao Nie Weisheng Zhao Jungang Miao Yutong Li Li Wang Xiaojun Wu 

机构地区：[1]Beihang University,Fert Beijing Institute,Advanced Innovation Center for Big Data and Brain Computing,School of Microelectronics,Beijing,China [2]Beihang University,School of Electronic and Information Engineering,Beijing,China [3]Chinese Academy of Sciences,Institute of Physics,Beijing National Laboratory for Condensed Matter Physics,Beijing,China [4]University of Chinese Academy of Sciences,School of Physical Sciences,Beijing,China [5]Beihang University,Beihang-Goertek Joint Microelectronics Institute,Qingdao Research Institute,Qingdao,China [6]Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,China

出　　处：《Advanced Photonics》2020年第6期14-22,共9页先进光子学（英文）

基　　金：This work was supported by Beijing Natural Science Foundation(Grant No.4194083);the National Natural Science Foundation of China(Grant Nos.61905007,61774013,11827807,and 61731001);the National Key R&D Program of China(Grant Nos.2019YFB2203102 and 2018YFB0407602);the International Collaboration Project(Grant No.B16001);the National Key Technology Program of China(Grant No.2017ZX01032101);the Open Project Program of Wuhan National Laboratory for Optoelectronics(Grant No.2018WNLOKF001).

摘　　要：Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding numerous applications,such as imaging,information encryption,and all-optical coherent control of terahertz nonlinear phenomena.Topological insulators featuring unique spinmomentum-locked surface state have already exhibited very promising prospects in terahertz emission,detection,and modulation,which may lay a foundation for future on-chip topological insulator-based terahertz systems.However,polarization-shaped terahertz emitters based on topological insulators with an arbitrarily manipulated temporal evolution of the amplitude and the electric-field vector direction have not yet been explored.We systematically investigated the terahertz radiation from topological insulator Bi2Te3 nanofilms driven by femtosecond laser pulses and successfully realized the generation of efficient chiral terahertz waves with controllable chirality,ellipticity,and principal axis.The convenient engineering of the chiral terahertz waves was interpreted by a photogalvanic effect(PGE)-induced photocurrent,while the linearly polarized terahertz waves originated from linear PGE-induced shift currents.Our work not only provides further understanding of femtosecond coherent control of ultrafast spin currents but also describes an effective way to generate spin-polarized terahertz waves at the source.

关 键 词：spin-polarized terahertz MANIPULATION topological insulator photogalvanic effect 

分 类 号：O469[理学—凝聚态物理]