Light Trapping by Non-Hermitian Thin Films

Fuente: arXiv
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Main Authors: Grineviciute, Lina, Lukosiunas, Ignas, Nikitina, Julianija, Selskis, Algirdas, Meskelaite, Indre, Gailevicius, Darius, Staliunas, Kestutis
Format: Preprint
Published: 2024
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author Grineviciute, Lina
Lukosiunas, Ignas
Nikitina, Julianija
Selskis, Algirdas
Meskelaite, Indre
Gailevicius, Darius
Staliunas, Kestutis
author_facet Grineviciute, Lina
Lukosiunas, Ignas
Nikitina, Julianija
Selskis, Algirdas
Meskelaite, Indre
Gailevicius, Darius
Staliunas, Kestutis
contents One of the exceptional features of non-Hermitian systems is the unidirectional wave interactions. Simultaneous modulation of the real and the imaginary part of the interaction potentials (of the refractive index and the gain/loss in the case of optical systems) can result in unequal coupling coefficients between the fields of different parts of the system. The unidirectional coupling can also be arranged not only between the internal fields of the system but also between internal fields and external radiation. At a particular (exceptional) point the situation can be achieved, that the external radiation is efficiently coupled into the system, but the internal radiation cannot escape backwards. In this way, the incident radiation can be trapped inside the non-Hermitian system and, eventually, can be efficiently absorbed there. We realize this idea in non-Hermitically modulated thin films. The modulation consists of a Hermitian part - the periodic corrugation of the surfaces of a thin film, and a non-Hermitian part - the modulation of losses along the film. We prove numerically and demonstrate experimentally that the incident radiation, coupled with such a non-Hermitian thin film, is unidirectionally trapped into a planar mode of the film, does not escape from the film (or escape weakly due to experimental imperfections), and is efficiently absorbed there.
format Preprint
id arxiv_https___arxiv_org_abs_2410_15101
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Light Trapping by Non-Hermitian Thin Films
Grineviciute, Lina
Lukosiunas, Ignas
Nikitina, Julianija
Selskis, Algirdas
Meskelaite, Indre
Gailevicius, Darius
Staliunas, Kestutis
Optics
One of the exceptional features of non-Hermitian systems is the unidirectional wave interactions. Simultaneous modulation of the real and the imaginary part of the interaction potentials (of the refractive index and the gain/loss in the case of optical systems) can result in unequal coupling coefficients between the fields of different parts of the system. The unidirectional coupling can also be arranged not only between the internal fields of the system but also between internal fields and external radiation. At a particular (exceptional) point the situation can be achieved, that the external radiation is efficiently coupled into the system, but the internal radiation cannot escape backwards. In this way, the incident radiation can be trapped inside the non-Hermitian system and, eventually, can be efficiently absorbed there. We realize this idea in non-Hermitically modulated thin films. The modulation consists of a Hermitian part - the periodic corrugation of the surfaces of a thin film, and a non-Hermitian part - the modulation of losses along the film. We prove numerically and demonstrate experimentally that the incident radiation, coupled with such a non-Hermitian thin film, is unidirectionally trapped into a planar mode of the film, does not escape from the film (or escape weakly due to experimental imperfections), and is efficiently absorbed there.
title Light Trapping by Non-Hermitian Thin Films
topic Optics
url https://arxiv.org/abs/2410.15101