Observation of unidirectional backscattering-immune topological electromagnetic states
One of the most striking phenomena in condensed-matter physics is the quantum Hall effect, which arises in two-dimensional electron systems subject to a large magnetic field applied perpendicular to the plane in which the electrons reside. In such circumstances, current is carried by electrons along...
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Nature Publishing Group
2014
|
| Online Access: | http://hdl.handle.net/1721.1/88469 https://orcid.org/0000-0002-7184-5831 https://orcid.org/0000-0002-7244-3682 |
| _version_ | 1826207640798101504 |
|---|---|
| author | Wang, Zheng Soljacic, Marin Chong, Y. Joannopoulos, John |
| author2 | Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies |
| author_facet | Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies Wang, Zheng Soljacic, Marin Chong, Y. Joannopoulos, John |
| author_sort | Wang, Zheng |
| collection | MIT |
| description | One of the most striking phenomena in condensed-matter physics is the quantum Hall effect, which arises in two-dimensional electron systems subject to a large magnetic field applied perpendicular to the plane in which the electrons reside. In such circumstances, current is carried by electrons along the edges of the system, in so-called chiral edge states (CESs). These are states that, as a consequence of nontrivial topological properties of the bulk electronic band structure, have a unique directionality and are robust against scattering from disorder. Recently, it was theoretically predicted that electromagnetic analogues of such electronic edge states could be observed in photonic crystals, which are materials having refractive-index variations with a periodicity comparable to the wavelength of the light passing through them. Here we report the experimental realization and observation of such electromagnetic CESs in a magneto-optical photonic crystal fabricated in the microwave regime. We demonstrate that, like their electronic counterparts, electromagnetic CESs can travel in only one direction and are very robust against scattering from disorder; we find that even large metallic scatterers placed in the path of the propagating edge modes do not induce reflections. These modes may enable the production of new classes of electromagnetic device and experiments that would be impossible using conventional reciprocal photonic states alone. Furthermore, our experimental demonstration and study of photonic CESs provides strong support for the generalization and application of topological band theories to classical and bosonic systems, and may lead to the realization and observation of topological phenomena in a generally much more controlled and customizable fashion than is typically possible with electronic systems. |
| first_indexed | 2024-09-23T13:52:39Z |
| format | Article |
| id | mit-1721.1/88469 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:52:39Z |
| publishDate | 2014 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | mit-1721.1/884692024-03-19T02:16:36Z Observation of unidirectional backscattering-immune topological electromagnetic states Wang, Zheng Soljacic, Marin Chong, Y. Joannopoulos, John Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies Massachusetts Institute of Technology. Department of Physics Wang, Zheng Chong, Yidong Joannopoulos, John D. Soljacic, Marin One of the most striking phenomena in condensed-matter physics is the quantum Hall effect, which arises in two-dimensional electron systems subject to a large magnetic field applied perpendicular to the plane in which the electrons reside. In such circumstances, current is carried by electrons along the edges of the system, in so-called chiral edge states (CESs). These are states that, as a consequence of nontrivial topological properties of the bulk electronic band structure, have a unique directionality and are robust against scattering from disorder. Recently, it was theoretically predicted that electromagnetic analogues of such electronic edge states could be observed in photonic crystals, which are materials having refractive-index variations with a periodicity comparable to the wavelength of the light passing through them. Here we report the experimental realization and observation of such electromagnetic CESs in a magneto-optical photonic crystal fabricated in the microwave regime. We demonstrate that, like their electronic counterparts, electromagnetic CESs can travel in only one direction and are very robust against scattering from disorder; we find that even large metallic scatterers placed in the path of the propagating edge modes do not induce reflections. These modes may enable the production of new classes of electromagnetic device and experiments that would be impossible using conventional reciprocal photonic states alone. Furthermore, our experimental demonstration and study of photonic CESs provides strong support for the generalization and application of topological band theories to classical and bosonic systems, and may lead to the realization and observation of topological phenomena in a generally much more controlled and customizable fashion than is typically possible with electronic systems. 2014-07-22T15:30:38Z 2014-07-22T15:30:38Z 2009-10 2009-06 Article http://purl.org/eprint/type/JournalArticle 0028-0836 1476-4687 http://hdl.handle.net/1721.1/88469 Wang, Zheng, Yidong Chong, J. D. Joannopoulos, and Marin Soljacic. “Observation of Unidirectional Backscattering-Immune Topological Electromagnetic States.” Nature 461, no. 7265 (October 8, 2009): 772–775. https://orcid.org/0000-0002-7184-5831 https://orcid.org/0000-0002-7244-3682 en_US http://dx.doi.org/10.1038/nature08293 Nature Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Nature Publishing Group MIT web domain |
| spellingShingle | Wang, Zheng Soljacic, Marin Chong, Y. Joannopoulos, John Observation of unidirectional backscattering-immune topological electromagnetic states |
| title | Observation of unidirectional backscattering-immune topological electromagnetic states |
| title_full | Observation of unidirectional backscattering-immune topological electromagnetic states |
| title_fullStr | Observation of unidirectional backscattering-immune topological electromagnetic states |
| title_full_unstemmed | Observation of unidirectional backscattering-immune topological electromagnetic states |
| title_short | Observation of unidirectional backscattering-immune topological electromagnetic states |
| title_sort | observation of unidirectional backscattering immune topological electromagnetic states |
| url | http://hdl.handle.net/1721.1/88469 https://orcid.org/0000-0002-7184-5831 https://orcid.org/0000-0002-7244-3682 |
| work_keys_str_mv | AT wangzheng observationofunidirectionalbackscatteringimmunetopologicalelectromagneticstates AT soljacicmarin observationofunidirectionalbackscatteringimmunetopologicalelectromagneticstates AT chongy observationofunidirectionalbackscatteringimmunetopologicalelectromagneticstates AT joannopoulosjohn observationofunidirectionalbackscatteringimmunetopologicalelectromagneticstates |