Surface-wave-assisted nonreciprocity in spatio-temporally modulated metasurfaces.

Autor:	Cardin AE; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.; Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA., Silva SR; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Vardeny SR; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Padilla WJ; Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA., Saxena A; Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Taylor AJ; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Kort-Kamp WJM; Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Chen HT; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA., Dalvit DAR; Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA. dalvit@lanl.gov., Azad AK; Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA. aazad@lanl.gov.
Jazyk:	angličtina
Zdroj:	Nature communications [Nat Commun] 2020 Mar 19; Vol. 11 (1), pp. 1469. Date of Electronic Publication: 2020 Mar 19.
DOI:	10.1038/s41467-020-15273-1
Abstrakt:	Emerging photonic functionalities are mostly governed by the fundamental principle of Lorentz reciprocity. Lifting the constraints imposed by this principle could circumvent deleterious effects that limit the performance of photonic systems. Most efforts to date have been limited to waveguide platforms. Here, we propose and experimentally demonstrate a spatio-temporally modulated metasurface capable of complete violation of Lorentz reciprocity by reflecting an incident beam into far-field radiation in forward scattering, but into near-field surface waves in reverse scattering. These observations are shown both in nonreciprocal beam steering and nonreciprocal focusing. We also demonstrate nonreciprocal behavior of propagative-only waves in the frequency- and momentum-domains, and simultaneously in both. We develop a generalized Bloch-Floquet theory which offers physical insights into Lorentz nonreciprocity for arbitrary spatial phase gradients, and its predictions are in excellent agreement with experiments. Our work opens exciting opportunities in applications where free-space nonreciprocal wave propagation is desired.
Databáze:	MEDLINE
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