Electrically actuated varifocal lens based on liquid-crystal-embedded dielectric metasurfaces

Fuente: arXiv
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Bibliographic Details
Main Authors: Bosch, Melissa, Shcherbakov, Maxim R., Won, Kanghee, Lee, Hong-Seok, Kim, Young, Shvets, Gennady
Format: Preprint
Published: 2021
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author Bosch, Melissa
Shcherbakov, Maxim R.
Won, Kanghee
Lee, Hong-Seok
Kim, Young
Shvets, Gennady
author_facet Bosch, Melissa
Shcherbakov, Maxim R.
Won, Kanghee
Lee, Hong-Seok
Kim, Young
Shvets, Gennady
contents Compact varifocal lenses are essential to various imaging and vision technologies. However, existing varifocal elements typically rely on mechanically-actuated systems with limited tuning speeds and scalability. Here, an ultrathin electrically controlled varifocal lens based on a liquid crystal (LC) encapsulated semiconductor metasurface is demonstrated. Enabled by the field-dependent LC anisotropy, applying a voltage bias across the LC cell modifies the local phase response of the silicon meta-atoms, in turn modifying the focal length of the metalens. In a numerical implementation, a voltage-actuated metalens with continuous zoom and up to 20% total focal shift is demonstrated. The concept of LC-based metalens is experimentally verified through the design and fabrication of a bifocal metalens that facilitates high-contrast switching between two discrete focal lengths upon application of a 3.2 V$_{\rm pp}$ voltage bias. Owing to their ultrathin thickness and adaptable design, LC-driven semiconductor metasurfaces open new opportunities for compact varifocal lensing in a diversity of modern imaging applications.
format Preprint
id arxiv_https___arxiv_org_abs_2101_09325
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Electrically actuated varifocal lens based on liquid-crystal-embedded dielectric metasurfaces
Bosch, Melissa
Shcherbakov, Maxim R.
Won, Kanghee
Lee, Hong-Seok
Kim, Young
Shvets, Gennady
Optics
Applied Physics
Compact varifocal lenses are essential to various imaging and vision technologies. However, existing varifocal elements typically rely on mechanically-actuated systems with limited tuning speeds and scalability. Here, an ultrathin electrically controlled varifocal lens based on a liquid crystal (LC) encapsulated semiconductor metasurface is demonstrated. Enabled by the field-dependent LC anisotropy, applying a voltage bias across the LC cell modifies the local phase response of the silicon meta-atoms, in turn modifying the focal length of the metalens. In a numerical implementation, a voltage-actuated metalens with continuous zoom and up to 20% total focal shift is demonstrated. The concept of LC-based metalens is experimentally verified through the design and fabrication of a bifocal metalens that facilitates high-contrast switching between two discrete focal lengths upon application of a 3.2 V$_{\rm pp}$ voltage bias. Owing to their ultrathin thickness and adaptable design, LC-driven semiconductor metasurfaces open new opportunities for compact varifocal lensing in a diversity of modern imaging applications.
title Electrically actuated varifocal lens based on liquid-crystal-embedded dielectric metasurfaces
topic Optics
Applied Physics
url https://arxiv.org/abs/2101.09325