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Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene
In a semiconductor illuminated by a strong terahertz (THz) field, optically excited electron–hole pairs can recombine to emit light in a broad frequency comb evenly spaced by twice the THz frequency. Such high-order THz sideband generation is of interest both as an example of extreme nonlinear optic...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Pub. Group
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4200518/ https://www.ncbi.nlm.nih.gov/pubmed/25249245 http://dx.doi.org/10.1038/ncomms5854 |
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author | Crosse, J. A. Xu, Xiaodong Sherwin, Mark S. Liu, R. B. |
author_facet | Crosse, J. A. Xu, Xiaodong Sherwin, Mark S. Liu, R. B. |
author_sort | Crosse, J. A. |
collection | PubMed |
description | In a semiconductor illuminated by a strong terahertz (THz) field, optically excited electron–hole pairs can recombine to emit light in a broad frequency comb evenly spaced by twice the THz frequency. Such high-order THz sideband generation is of interest both as an example of extreme nonlinear optics and also as a method for ultrafast electro-optical modulation. So far, this phenomenon has only been observed with large field strengths (~10 kV cm(−1)), an obstacle for technological applications. Here we predict that bi-layer graphene generates high-order sidebands at much weaker THz fields. We find that a THz field of strength 1 kV cm(−1) can produce a high-sideband spectrum of about 30 THz, 100 times broader than in GaAs. The sidebands are generated despite the absence of classical collisions, with the quantum coherence of the electron–hole pairs enabling recombination. These remarkable features lower the barrier to desktop electro-optical modulation at THz frequencies, facilitating ultrafast optical communications. |
format | Online Article Text |
id | pubmed-4200518 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Nature Pub. Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-42005182014-10-21 Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene Crosse, J. A. Xu, Xiaodong Sherwin, Mark S. Liu, R. B. Nat Commun Article In a semiconductor illuminated by a strong terahertz (THz) field, optically excited electron–hole pairs can recombine to emit light in a broad frequency comb evenly spaced by twice the THz frequency. Such high-order THz sideband generation is of interest both as an example of extreme nonlinear optics and also as a method for ultrafast electro-optical modulation. So far, this phenomenon has only been observed with large field strengths (~10 kV cm(−1)), an obstacle for technological applications. Here we predict that bi-layer graphene generates high-order sidebands at much weaker THz fields. We find that a THz field of strength 1 kV cm(−1) can produce a high-sideband spectrum of about 30 THz, 100 times broader than in GaAs. The sidebands are generated despite the absence of classical collisions, with the quantum coherence of the electron–hole pairs enabling recombination. These remarkable features lower the barrier to desktop electro-optical modulation at THz frequencies, facilitating ultrafast optical communications. Nature Pub. Group 2014-09-24 /pmc/articles/PMC4200518/ /pubmed/25249245 http://dx.doi.org/10.1038/ncomms5854 Text en Copyright © 2014, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. http://creativecommons.org/licenses/by-nc-sa/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/4.0/ |
spellingShingle | Article Crosse, J. A. Xu, Xiaodong Sherwin, Mark S. Liu, R. B. Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title | Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title_full | Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title_fullStr | Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title_full_unstemmed | Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title_short | Theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
title_sort | theory of low-power ultra-broadband terahertz sideband generation in bi-layer graphene |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4200518/ https://www.ncbi.nlm.nih.gov/pubmed/25249245 http://dx.doi.org/10.1038/ncomms5854 |
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