Electrically Reconfigurable Nonvolatile Metasurface Using Low-Loss Optical Phase Change Material

TL;DR

This paper introduces the first electrically reconfigurable nonvolatile metasurfaces using a low-loss optical phase change material, achieving broad spectral tuning and dynamic beam steering.

Contribution

It demonstrates a novel active metasurface device based on Ge2Sb2Se4Te1 with record spectral tuning and high optical contrast, enabling advanced reconfigurable optics.

Findings

Record half-octave spectral tuning range

Optical contrast over 400%

Dynamic beam steering demonstration

Abstract

Active metasurfaces promise reconfigurable optics with drastically improved compactness, ruggedness, manufacturability, and functionality compared to their traditional bulk counterparts. Optical phase change materials (O-PCMs) offer an appealing material solution for active metasurface devices with their large index contrast and nonvolatile switching characteristics. Here we report what we believe to be the first electrically reconfigurable nonvolatile metasurfaces based on O-PCMs. The O-PCM alloy used in the devices, Ge2Sb2Se4Te1 (GSST), uniquely combines giant non-volatile index modulation capability, broadband low optical loss, and a large reversible switching volume, enabling significantly enhanced light-matter interactions within the active O-PCM medium. Capitalizing on these favorable attributes, we demonstrated continuously tunable active metasurfaces with record half-octave spectral tuning range and large optical contrast of over 400%. We further prototyped a polarization-insensitive phase-gradient metasurface to realize dynamic optical beam steering.