Reconfigurable focusing and defocusing meta lens using Sb2Se3 phase change material

Phase-change materials offer a compelling platform for low power consumption active integrated optical circuits and meta optics, with their large optical index contrast (Δn, Δk) and nonvolatile phase transition^1,2. Here, we demonstrate an electrically driven tunable meta lens in telecom range by exploring the full potential of a low absorption loss and high refractive index contrast PCM alloy, Sb₂Se_3, to realize non-volatile, reversible, fast focusing and defocusing meta lens in the 1550 telecom spectral range. With a fixed geometric design, the phase change material of Sb₂Se₃ switches the focusing length of a silicon photonic meta lens between two different values nonviolently. This unique functionality of the hybrid meta surface is attributed to the fact that the silicon’s refractive index is in the middle of the two convertible states in the optical phase change material. The transparency of Sb₂Se₃ in both states enables near phase-only meta surface structures. Our heterostructure architecture capitalizes over the integration of a robust resistive transparent microheater ITO (Indium Tin Oxide) decoupled from meta lens enabling good model to overlap with PCM meta pillars enables high transmission efficiency. The project be experimentally demonstrating an electrically reconfigurable phase-change meta lens capable of modulation an incident light beam into focusing of defocusing two different statures. This work represents a critical advance towards the development of integrable dynamic meta lens and their potential for beamforming applications.