Active Metasurface Optics Based on Chalcogenide Phase Change Materials

Phase change materials or PCMs are truly remarkable compounds whose unique switchable properties have fueled an explosion of emerging applications in electronics and photonics. Traditional PCMs suffer from large optical losses even in their dielectric states, which fundamentally limits the performance of optical devices based on the materials. To resolve the issue, we have demonstrated a new PCM Ge-Sb-Se-Te (GSST) with broadband low loss characteristics. In this talk, we will review an array of reconfigurable photonic devices enabled by the low-loss PCM, including electrically tunable metasurfaces, beam steering optics, and parfocal zoom lenses.