Topologically protected refraction of robust kink states in valley photonic crystals
Recently discovered1,2 valley photonic crystals (VPCs) mimic many of the unusual properties of two-dimensional (2D) gapped valleytronic materials3,4,5,6,7,8,9. Of the utmost interest to optical communications is their ability to support topologically protected chiral edge (kink) states3,4,5,6,7,8,9...
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| Materialtyp: | Journal Article |
| Språk: | English |
| Publicerad: |
2019
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| Länkar: | https://hdl.handle.net/10356/88937 http://hdl.handle.net/10220/48348 |
| _version_ | 1826111704367366144 |
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| author | Gao, Fei Xue, Haoran Yang, Zhaoju Lai, Kueifu Yu, Yang Lin, Xiao Chong, Yidong Shvets, Gennady Zhang, Baile |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Gao, Fei Xue, Haoran Yang, Zhaoju Lai, Kueifu Yu, Yang Lin, Xiao Chong, Yidong Shvets, Gennady Zhang, Baile |
| author_sort | Gao, Fei |
| collection | NTU |
| description | Recently discovered1,2 valley photonic crystals (VPCs) mimic many of the unusual properties of two-dimensional (2D) gapped valleytronic materials3,4,5,6,7,8,9. Of the utmost interest to optical communications is their ability to support topologically protected chiral edge (kink) states3,4,5,6,7,8,9 at the internal domain wall between two VPCs with opposite valley-Chern indices. Here we experimentally demonstrate valley-polarized kink states with polarization multiplexing in VPCs, designed from a spin-compatible four-band model. When the valley pseudospin is conserved, we show that the kink states exhibit nearly perfect out-coupling efficiency into directional beams, through the intersection between the internal domain wall and the external edge separating the VPCs from ambient space. The out-coupling behaviour remains topologically protected even when we break the spin-like polarization degree of freedom (DOF), by introducing an effective spin–orbit coupling in one of the VPC domains. This also constitutes the first realization of spin–valley locking for topological valley transport. |
| first_indexed | 2024-10-01T02:55:09Z |
| format | Journal Article |
| id | ntu-10356/88937 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:55:09Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | ntu-10356/889372023-02-28T19:31:31Z Topologically protected refraction of robust kink states in valley photonic crystals Gao, Fei Xue, Haoran Yang, Zhaoju Lai, Kueifu Yu, Yang Lin, Xiao Chong, Yidong Shvets, Gennady Zhang, Baile School of Physical and Mathematical Sciences Centre for Disruptive Photonic Technologies Photonic Crystals DRNTU::Science::Physics Metamaterials Recently discovered1,2 valley photonic crystals (VPCs) mimic many of the unusual properties of two-dimensional (2D) gapped valleytronic materials3,4,5,6,7,8,9. Of the utmost interest to optical communications is their ability to support topologically protected chiral edge (kink) states3,4,5,6,7,8,9 at the internal domain wall between two VPCs with opposite valley-Chern indices. Here we experimentally demonstrate valley-polarized kink states with polarization multiplexing in VPCs, designed from a spin-compatible four-band model. When the valley pseudospin is conserved, we show that the kink states exhibit nearly perfect out-coupling efficiency into directional beams, through the intersection between the internal domain wall and the external edge separating the VPCs from ambient space. The out-coupling behaviour remains topologically protected even when we break the spin-like polarization degree of freedom (DOF), by introducing an effective spin–orbit coupling in one of the VPC domains. This also constitutes the first realization of spin–valley locking for topological valley transport. MOE (Min. of Education, S’pore) Accepted version 2019-05-23T08:55:33Z 2019-12-06T17:14:07Z 2019-05-23T08:55:33Z 2019-12-06T17:14:07Z 2018 Journal Article Gao, F., Xue, H., Yang, Z., Lai, K., Yu, Y., Lin, X., . . . Zhang, B. (2018). Topologically protected refraction of robust kink states in valley photonic crystals. Nature Physics, 14(2), 140-144. doi:10.1038/nphys4304 1745-2473 https://hdl.handle.net/10356/88937 http://hdl.handle.net/10220/48348 10.1038/nphys4304 en Nature Physics © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. This paper was published in Nature Physics and is made available with permission of Macmillan Publishers Limited, part of Springer Nature. 21 p. application/pdf |
| spellingShingle | Photonic Crystals DRNTU::Science::Physics Metamaterials Gao, Fei Xue, Haoran Yang, Zhaoju Lai, Kueifu Yu, Yang Lin, Xiao Chong, Yidong Shvets, Gennady Zhang, Baile Topologically protected refraction of robust kink states in valley photonic crystals |
| title | Topologically protected refraction of robust kink states in valley photonic crystals |
| title_full | Topologically protected refraction of robust kink states in valley photonic crystals |
| title_fullStr | Topologically protected refraction of robust kink states in valley photonic crystals |
| title_full_unstemmed | Topologically protected refraction of robust kink states in valley photonic crystals |
| title_short | Topologically protected refraction of robust kink states in valley photonic crystals |
| title_sort | topologically protected refraction of robust kink states in valley photonic crystals |
| topic | Photonic Crystals DRNTU::Science::Physics Metamaterials |
| url | https://hdl.handle.net/10356/88937 http://hdl.handle.net/10220/48348 |
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