Magnetically tunable optical bound states in the continuum with arbitrary polarization and intrinsic chirality

Fuente: arXiv
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Main Authors: Tu, Qing-an, Zhou, Hongxin, Meng, Yan, Gong, Maohua, Gao, Zhen
Format: Preprint
Published: 2024
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author Tu, Qing-an
Zhou, Hongxin
Meng, Yan
Gong, Maohua
Gao, Zhen
author_facet Tu, Qing-an
Zhou, Hongxin
Meng, Yan
Gong, Maohua
Gao, Zhen
contents Optical bound states in the continuum (BICs), which are exotic localized eigenstates embedded in the continuum spectrum and topological polarization singularity in momentum space, have attracted great attentions in both fundamental and applied physics. Here, based on magneto-optical photonic crystal slab placed in external magnetic fields to break the time-reversal symmetry, we theoretically demonstrate magnetically tunable BICs with arbitrary polarization covering the entire Poincaré sphere and efficient off-Γ chiral emission of circularly polarized states. More interestingly, by further breaking the in-plane inversion symmetry of the magneto-optical photonic crystal slab to generate a pair of circularly polarized states (C point) spawning from the eliminated BICs and tuning the external magnetic field strength to move one C point to the Γ point, one at-Γ intrinsic chiral BICs with near-unity circular dichroism exceeding 0.99 and a high quality factor of 46000 owning to the preserved out-of-plane mirror symmetry can be observed. These findings may lead to a plethora of potential applications in chiral-optical effects, structured light, and tunable optical devices.
format Preprint
id arxiv_https___arxiv_org_abs_2406_11204
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetically tunable optical bound states in the continuum with arbitrary polarization and intrinsic chirality
Tu, Qing-an
Zhou, Hongxin
Meng, Yan
Gong, Maohua
Gao, Zhen
Optics
Optical bound states in the continuum (BICs), which are exotic localized eigenstates embedded in the continuum spectrum and topological polarization singularity in momentum space, have attracted great attentions in both fundamental and applied physics. Here, based on magneto-optical photonic crystal slab placed in external magnetic fields to break the time-reversal symmetry, we theoretically demonstrate magnetically tunable BICs with arbitrary polarization covering the entire Poincaré sphere and efficient off-Γ chiral emission of circularly polarized states. More interestingly, by further breaking the in-plane inversion symmetry of the magneto-optical photonic crystal slab to generate a pair of circularly polarized states (C point) spawning from the eliminated BICs and tuning the external magnetic field strength to move one C point to the Γ point, one at-Γ intrinsic chiral BICs with near-unity circular dichroism exceeding 0.99 and a high quality factor of 46000 owning to the preserved out-of-plane mirror symmetry can be observed. These findings may lead to a plethora of potential applications in chiral-optical effects, structured light, and tunable optical devices.
title Magnetically tunable optical bound states in the continuum with arbitrary polarization and intrinsic chirality
topic Optics
url https://arxiv.org/abs/2406.11204