Emergent spin and orbital angular momentum of light in twisted photonic bilayer

Fuente: arXiv
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Main Authors: Vyatkin, Egor S., Poshakinskiy, Alexander V., Tarasenko, Sergey A.
Format: Preprint
Published: 2024
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author Vyatkin, Egor S.
Poshakinskiy, Alexander V.
Tarasenko, Sergey A.
author_facet Vyatkin, Egor S.
Poshakinskiy, Alexander V.
Tarasenko, Sergey A.
contents We demonstrate that the optical response of twisted photonic bilayers, photonic counterparts of van der Waals structures, is sensitive to both spin angular momentum (SAM) and orbital angular momentum (OAM) of light. A beam of unpolarized light with zero angular momentum acquires SAM in transmission and OAM in reflection. The developed analytical theory and numerical calculations show that the SAM and OAM arise from distinct microscopic mechanisms and depend differently on the interlayer distance. The predicted phenomena do not require light absorption and are caused by the photon-helicity-dependent light diffraction by the moiré pattern, which inevitably occurs in the twisted structure, and the SAM-OAM conversion processes. We also reveal strong SAM and OAM in the moiré-diffracted beams. Our findings uncover a profound connection between the emergent SAM and OAM in twisted photonic systems offering new possibilities for angular-momentum-resolved light-matter interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2408_01274
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Emergent spin and orbital angular momentum of light in twisted photonic bilayer
Vyatkin, Egor S.
Poshakinskiy, Alexander V.
Tarasenko, Sergey A.
Optics
Mesoscale and Nanoscale Physics
We demonstrate that the optical response of twisted photonic bilayers, photonic counterparts of van der Waals structures, is sensitive to both spin angular momentum (SAM) and orbital angular momentum (OAM) of light. A beam of unpolarized light with zero angular momentum acquires SAM in transmission and OAM in reflection. The developed analytical theory and numerical calculations show that the SAM and OAM arise from distinct microscopic mechanisms and depend differently on the interlayer distance. The predicted phenomena do not require light absorption and are caused by the photon-helicity-dependent light diffraction by the moiré pattern, which inevitably occurs in the twisted structure, and the SAM-OAM conversion processes. We also reveal strong SAM and OAM in the moiré-diffracted beams. Our findings uncover a profound connection between the emergent SAM and OAM in twisted photonic systems offering new possibilities for angular-momentum-resolved light-matter interactions.
title Emergent spin and orbital angular momentum of light in twisted photonic bilayer
topic Optics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2408.01274