{"id":38,"date":"2024-05-30T11:26:07","date_gmt":"2024-05-30T09:26:07","guid":{"rendered":"https:\/\/www.fresnel.fr\/wp\/?p=38"},"modified":"2024-05-31T10:40:04","modified_gmt":"2024-05-31T08:40:04","slug":"hello-word-uk","status":"publish","type":"post","link":"https:\/\/www.fresnel.fr\/wp\/en\/hello-word-uk\/","title":{"rendered":"Linear frequency conversion with time-varying meta-surfaces"},"content":{"rendered":"

Linear frequency conversion with time-varying meta-surfaces<\/strong><\/p>\n

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Frequency conversion is usually achieved using non-linear materials. However, the field of dynamic metamaterials is likely, at least from a theoretical point of view, to offer an alternative technique to these conversion processes. This has been demonstrated by researchers at Fresnel Institute, in collaboration with other international teams. Dynamic metamaterials are known to broaden or generate a continuum of frequencies in response to quasi-monochromatic radiation. This property is conferred on them by parallel excitation (electrical, optical, etc.) enabling their physical parameters to be modified in real time at high frequency (optical, RF). This pump-probe configuration introduces a susceptibility \u00a0with 2 time variables, the first of which (t’) is associated with the causality principle (memory\/inertia\/dispersion\/absorption), and the second (t) with the real-time modification of the material’s memory. This dual temporal aspect calls for a reconsideration of Maxwell’s equations, where new degrees of freedom appear notably related to the time dependence \u00a0of dispersion. In this context, the researchers succeeded in identifying the class of susceptibilities capable of converting the frequency of the incident radiation into an arbitrary pre-established frequency, while respecting the principles of causality. This theoretical work has been established for conventional materials (notably linear) whose volume is reduced to the case of a meta-surface for simplification. The process can be generalized to a comb of arbitrary frequencies that could be imposed for reflection and\/or transmission. However, the number of parameters involved in the analytical form of the susceptibilities (24 in a 2-frequency conversion process) increases rapidly with the number of frequencies to be imposed.<\/p>\n

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Schematic diagram (left) of the linear frequency conversion process, with numerical results (right) for conversion efficiency in the special case of identical parameters..<\/em><\/figcaption><\/figure>\n

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DOI :<\/strong> 10.1103\/PhysRevResearch.6.013002 <\/a><\/p>\n

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Reference :<\/strong> Claude Amra, Ali Passian, Philippe Tchamitchian, Mauro Ettorre, Ahmed Alwakil, Juan Antonio Zapien, Paul Rouquette, Yannick Abautret, and Myriam Zerrad, \u201cLinear-frequency conversion with time-varying metasurfaces\u201d, <\/em>Phys. Rev. Research 6<\/strong>, 013002 \u2013 Published 2 January 2024<\/p>\n

Partners :\u00a0 <\/strong>Institut FRESNEL, ORNL – Oak Ridge National Laboratory, IETR – Institut d’\u00c9lectronique et des Technologies du num\u00e9Rique, CUHK – City University of Hong Kong, LAM – Laboratoire d’Astrophysique de Marseille<\/p>\n

Contact\u00a0 : <\/strong>Claude AMRA –\u00a0 claude.amra@fresnel.fr<\/a> or Myriam ZERRAD myriam.zerrad@fresnel.fr<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Linear frequency conversion with time-varying meta-surfaces   Frequency conversion is usually achieved using non-linear materials. […]<\/p>\n","protected":false},"author":1,"featured_media":905,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[62],"tags":[],"class_list":{"0":"post-38","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-non-classe-en","8":"entry"},"acf":[],"lang":"en","translations":{"en":38,"fr":1},"pll_sync_post":[],"_links":{"self":[{"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/posts\/38","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/comments?post=38"}],"version-history":[{"count":5,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/posts\/38\/revisions"}],"predecessor-version":[{"id":918,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/posts\/38\/revisions\/918"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/media\/905"}],"wp:attachment":[{"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/media?parent=38"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/categories?post=38"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fresnel.fr\/wp\/wp-json\/wp\/v2\/tags?post=38"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}