Massively Degenerate Coherent Perfect Absorption in Gradient-Index Fibers

Fuente: arXiv
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Autores principales: Hörner, Helmut, Özdemir, Şahin K., Rotter, Stefan
Formato: Preprint
Publicado: 2026
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author Hörner, Helmut
Özdemir, Şahin K.
Rotter, Stefan
author_facet Hörner, Helmut
Özdemir, Şahin K.
Rotter, Stefan
contents Coherent perfect absorbers (CPAs) have recently attracted considerable attention due to their ability to enhance light--matter interaction. By exploiting interference, CPAs enable even weakly absorbing materials to achieve complete absorption under appropriate excitation conditions. Generalizing this concept to the simultaneous absorption of arbitrary multimode input states remains challenging, however, since conventional implementations typically operate only for a single or a very small number of input channels. Here, we propose a compact realization of a multimode coherent perfect absorber based on a gradient-index (GRIN) fiber. Using the self-imaging property of the fiber, the bulky free-space architecture of previous approaches is replaced by a monolithic waveguiding platform that supports near-degenerate rephasing of many spatial modes. We show that standard GRIN profiles optimized for minimal intermodal dispersion enable highly efficient absorption of complex multimode fields, with field-of-view reflectivities well below \(1\%\) for realistic parameters. This approach provides a practical and scalable route toward efficient multimode absorption in fiber-based and integrated photonic systems, with potential applications in light harvesting, optical control, and imaging.
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id arxiv_https___arxiv_org_abs_2605_15998
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Massively Degenerate Coherent Perfect Absorption in Gradient-Index Fibers
Hörner, Helmut
Özdemir, Şahin K.
Rotter, Stefan
Optics
Coherent perfect absorbers (CPAs) have recently attracted considerable attention due to their ability to enhance light--matter interaction. By exploiting interference, CPAs enable even weakly absorbing materials to achieve complete absorption under appropriate excitation conditions. Generalizing this concept to the simultaneous absorption of arbitrary multimode input states remains challenging, however, since conventional implementations typically operate only for a single or a very small number of input channels. Here, we propose a compact realization of a multimode coherent perfect absorber based on a gradient-index (GRIN) fiber. Using the self-imaging property of the fiber, the bulky free-space architecture of previous approaches is replaced by a monolithic waveguiding platform that supports near-degenerate rephasing of many spatial modes. We show that standard GRIN profiles optimized for minimal intermodal dispersion enable highly efficient absorption of complex multimode fields, with field-of-view reflectivities well below \(1\%\) for realistic parameters. This approach provides a practical and scalable route toward efficient multimode absorption in fiber-based and integrated photonic systems, with potential applications in light harvesting, optical control, and imaging.
title Massively Degenerate Coherent Perfect Absorption in Gradient-Index Fibers
topic Optics
url https://arxiv.org/abs/2605.15998