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arXiv · 2104.08706

Broadband Omni-resonant Coherent Perfect Absorption in Graphene

Ali K. Jahromi·Massimo L. Villinger·Ahmed El Halawany·Soroush Shabahang·H. Esat Kondakci·Joshua D. Perlstein·Ayman F. Abouraddy
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Abstract

Coherent perfect absorption (CPA) refers to interferometrically induced complete absorption of incident light by a partial absorber independently of its intrinsic absorption (which may be vanishingly small) or its thickness. CPA is typically realized in a resonant device, and thus cannot be achieved over a broad continuous spectrum, which thwarts its applicability to photodetectors and solar cells, for example. Here, we demonstrate broadband omni-resonant CPA by placing a thin weak absorber in a planar cavity and pre-conditioning the incident optical field by introducing judicious angular dispersion. We make use of monolayer graphene embedded in silica as the absorber and boost its optical absorption from ~1.6% to ~60% over a bandwidth of ~70 nm in the visible. Crucially, an analytical model demonstrates that placement of the graphene monolayer at a peak in the cavity standing-wave field is not necessary to achieve CPA, contrary to conventional wisdom.

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Ali K. Jahromi, Massimo L. Villinger, Ahmed El Halawany, Soroush Shabahang, H. Esat Kondakci, Joshua D. Perlstein, Ayman F. Abouraddy. 2021-04-18. Broadband Omni-resonant Coherent Perfect Absorption in Graphene. https://arxiv.org/abs/2104.08706

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