Reconfigurable Flat Optics with Programmable Reflection Am- plitude Using Lithography-Free Phase-Change Materials Ultra Thin Films

We experimentally demonstrate a very large dynamic optical reflection modulation from a simple unpatterned layered stack of phase-change materials ultrathin films. Specifically, we theoretically and experimentally demonstrate that properly designed deeply sub-wavelength GeSbTe (GST) films on a metal...

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Bibliographic Details
Published in:Advanced optical materials 2020-11
Main Authors: Cueff, Sébastien, Taute, Arnaud X, Bourgade, Antoine, Lumeau, Julien, Monfray, Stephane, Song, Qinghua, Genevet, Patrice, Letartre, Xavier, Berguiga, L
Format: Article
Language:English
Subjects:
Engineering Sciences
Optics
Photonic
Online Access:Get full text
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Summary:We experimentally demonstrate a very large dynamic optical reflection modulation from a simple unpatterned layered stack of phase-change materials ultrathin films. Specifically, we theoretically and experimentally demonstrate that properly designed deeply sub-wavelength GeSbTe (GST) films on a metallic mirror produce a dynamic modulation of light in the near-infrared from very strong reflection (R > 80%) to perfect absorption (A > 99, 97%) by simply switching the crystalline state of the phase-change material. While the amplitude of modulation can lead to an optical contrast up to 10 6 , we can also actively "write" intermediate levels of reflection in between extreme values, corresponding to partial crystallization of the GST layer. We further explore several layered system designs and provide guidelines to tailor the wavelength efficiency range, the angle of operation and the degree of crystallization leading to perfect absorption.
ISSN:2195-1071
2195-1071
DOI:10.1002/adom.202001291