Electrically reconfigurable phase-change transmissive metasurface

TL;DR

This paper presents a scalable, electrically reconfigurable transmissive metasurface using phase-change materials, enabling non-volatile optical switching with potential applications in adaptive optics and photonics.

Contribution

It demonstrates a large-area, electrically switchable PCM-based transmissive filter with reliable switching and a significant contrast ratio, advancing reconfigurable optical device development.

Findings

200 μm × 200 μm switching area achieved

Switching contrast ratio of 5.5 dB demonstrated

Reversible switching for 1250 cycles before degradation

Abstract

Programmable and reconfigurable optics hold significant potential for transforming a broad spectrum of applications, spanning space explorations to biomedical imaging, gas sensing, and optical cloaking. The ability to adjust the optical properties of components like filters, lenses, and beam steering devices could result in dramatic reductions in size, weight, and power consumption in future optoelectronic devices. Among the potential candidates for reconfigurable optics, chalcogenide-based phase change materials (PCMs) offer great promise due to their non-volatile and analogue switching characteristics. Although PCM have found widespread use in electronic data storage, these memory devices are deeply sub-micron-sized. To incorporate phase change materials into free-space optical components, it is essential to scale them up to beyond several hundreds of microns while maintaining reliable switching characteristics. This study demonstrated a non-mechanical, non-volatile transmissive filter based on low-loss PCMs with a 200 $\mu$m$ \times $200 $\mu$m switching area. The device/metafilter can be consistently switched between low- and high-transmission states using electrical pulses with a switching contrast ratio of 5.5 dB. The device was reversibly switched for 1250 cycles before accelerated degradation took place. The work represents an important step toward realizing free-space reconfigurable optics based on PCMs.