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Cheng L, Xiong Y, Kang L, Gao Y, Chang Q, Chen M, Qi J, Yang H, Liu Z, Song JC, Chia EE. Giant photon momentum locked THz emission in a centrosymmetric Dirac semimetal. SCIENCE ADVANCES 2023; 9:eadd7856. [PMID: 36598995 PMCID: PMC9812375 DOI: 10.1126/sciadv.add7856] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Strong second-order optical nonlinearities often require broken material centrosymmetry, thereby limiting the type and quality of materials used for nonlinear optical devices. Here, we report a giant and highly tunable terahertz (THz) emission from thin polycrystalline films of the centrosymmetric Dirac semimetal PtSe2. Our PtSe2 THz emission is turned on at oblique incidence and locked to the photon momentum of the incident pump beam. Notably, we find an emitted THz efficiency that is giant: It is two orders of magnitude larger than the standard THz-generating nonlinear crystal ZnTe and has values approaching that of the noncentrosymmetric topological material TaAs. Further, PtSe2 THz emission displays THz sign and amplitude that is controlled by the incident pump polarization and helicity state even as optical absorption is only weakly polarization dependent and helicity independent. Our work demonstrates how photon drag can activate pronounced optical nonlinearities that are available even in centrosymmetric Dirac materials.
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Affiliation(s)
- Liang Cheng
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Ying Xiong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Lixing Kang
- Division of Advanced Materials, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
| | - Yu Gao
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Qing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Mengji Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Jingbo Qi
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637371, Singapore
| | - Justin C.W. Song
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Elbert E. M. Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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Mikheev GM, Kogai VY, Mikheev KG, Mogileva TN, Saushin AS, Svirko YP. Interaction of polarization-sensitive surface photocurrents in semitransparent CuSe/Se film. OPTICS EXPRESS 2021; 29:2112-2123. [PMID: 33726412 DOI: 10.1364/oe.415043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
We demonstrate that the transverse polarization-sensitive photoresponse of the CuSe/Se nanocomposite film deposited on a transparent substrate depends on whether the film is irradiated from the air side or substrate side. In particular, the nanosecond photocurrent pulse is either bipolar or unipolar pulse depending on which interface beam hits first. The observed phenomenon can be described in terms of the interplay between counter-propagating photocurrents generated at the air/nanocomposite and substrate/nanocomposite interfaces due to the surface photogalvanic effect. Our experimental findings can be employed to control the amplitude and temporal profile of the photoresponse by changing the polarization of the excitation laser beam.
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Ye W, Liu Y, Liu J, Horsley SAR, Wen S, Zhang S. Photonic Hall effect and helical Zitterbewegung in a synthetic Weyl system. LIGHT, SCIENCE & APPLICATIONS 2019; 8:49. [PMID: 31149334 PMCID: PMC6538614 DOI: 10.1038/s41377-019-0160-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 04/09/2019] [Accepted: 05/06/2019] [Indexed: 05/31/2023]
Abstract
Systems supporting Weyl points have gained increasing attention in condensed physics, photonics and acoustics due to their rich physics, such as Fermi arcs and chiral anomalies. Acting as sources or drains of Berry curvature, Weyl points exhibit a singularity of the Berry curvature at their core. It is, therefore, expected that the induced effect of the Berry curvature can be dramatically enhanced in systems supporting Weyl points. In this work, we construct synthetic Weyl points in a photonic crystal that consists of a honeycomb array of coupled rods with slowly varying radii along the direction of propagation. The system possesses photonic Weyl points in the synthetic space of two momenta plus an additional physical parameter with an enhanced Hall effect resulting from the large Berry curvature in the vicinity of the Weyl point. Interestingly, a helical Zitterbewegung (ZB) is observed when the wave packet traverses very close to a Weyl point, which is attributed to the contribution of the non-Abelian Berry connection arising from the near degenerate eigenstates.
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Affiliation(s)
- Weimin Ye
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073 Changsha, China
| | - Yachao Liu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, 410082 Changsha, China
- School of Physics & Astronomy, University of Birmingham, Birmingham, B15 2TT UK
| | - Jianlong Liu
- Department of Physics, Harbin Institute of Technology, 150001 Harbin, China
| | - Simon A. R. Horsley
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL UK
| | - Shuangchun Wen
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, 410082 Changsha, China
| | - Shuang Zhang
- School of Physics & Astronomy, University of Birmingham, Birmingham, B15 2TT UK
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