Reversible optical tuning of GeSbTe phase-change metasurface spectral filters for mid-wave infrared imaging.


Type
Article
Change log
Authors
Borg, Stephen 
Bartram, Scott 
Kim, Hyun Jung 
Abstract

Tunable narrowband spectral filtering across arbitrary optical wavebands is highly desirable in a plethora of applications, from chemical sensing and hyperspectral imaging to infrared astronomy. Yet, the ability to reconfigure the optical properties, with full reversibility, of a solid-state large-area narrowband filter remains elusive. Existing solutions require either moving parts, have slow response times, or provide limited spectral coverage. Here, we demonstrate a 1-inch diameter continuously tunable, fully reversible, all-solid-state, narrowband phase-change metasurface filter based on a GeSbTe-225 (GST)-embedded plasmonic nanohole array. The passband of the presented device is ∼74nm with ∼70% transmittance and operates across the 3-5 µm thermal imaging waveband. Continuous, reconfigurable tuning is achieved by exploiting intermediate GST phases via optical switching with a single nanosecond laser pulse, and material stability is verified through multiple switching cycles. We further demonstrate multispectral thermal imaging in the mid-wave infrared using our active phase-change metasurfaces. Our results pave the way for highly functional, reduced power, compact hyperspectral imaging systems and customizable optical filters for real-world system integration.

Description
Keywords
Journal Title
Optica
Conference Name
Journal ISSN
2334-2536
Volume Title
7
Publisher
Sponsorship
Engineering and Physical Sciences Research Council (EP/R003599/1)
Cancer Research UK (24669)