Electrically driven programmable phase-change meta-switch reaching 80% efficiency

TL;DR

This paper demonstrates an electrically reprogrammable metasurface using phase-change material GST, achieving high efficiency, large reflectance contrast, and fast switching, advancing dynamic optical device capabilities.

Contribution

The work introduces a hybrid plasmonic-PCM metasurface with record electrical modulation and spectral tuning, enabling fast, reversible, and multilevel optical control.

Findings

Reflectance contrast of 80% achieved

Spectral tuning over 250 nm demonstrated

Switching speed potentially reaching a few kHz

Abstract

Despite recent advances in active metaoptics, wide dynamic range combined with high-speed reconfigurable solutions is still elusive. Phase-change materials (PCMs) offer a compelling platform for metasurface optical elements, owing to the large index contrast and fast yet stable phase transition properties. Here, we experimentally demonstrate an in situ electrically-driven reprogrammable metasurface by harnessing the unique properties of a phase-change chalcogenide alloy, Ge$_{2}$Sb$_{2}$Te$_{5}$ (GST), in order to realize fast, non-volatile, reversible, multilevel, and pronounced optical modulation in the near-infrared spectral range. Co-optimized through a multiphysics analysis, we integrate an efficient heterostructure resistive microheater that indirectly heats and transforms the embedded GST film without compromising the optical performance of the metasurface even after several reversible phase transitions. A hybrid plasmonic-PCM meta-switch with a record electrical modulation of the reflectance over eleven-fold (an absolute reflectance contrast reaching 80%), unprecedented quasi-continuous spectral tuning over 250 nm, and switching speed that can potentially reach a few kHz is presented. Our work represents a significant step towards the development of fully integrable dynamic metasurfaces and their potential for beamforming applications.