Low Noise and Drift Reconfigurable Solution-Processed Chalcogenide Phase Change Metasurfaces

Chalcogenide glasses are increasingly favoured as the programmable layer of choice in reconfigurable optoelectronic platforms, enabling diverse signal modulation, display, and memory device applications over the past decade. These applications capitalize on the amorphous-to-crystalline phase transition of these alloys, often produced using expensive ultrahigh-vacuum physical vapor deposition (PVD) methods. Here, a cost-effective, solution-processed approach is presented to synthesizing chalcogenide phase change materials (PCMs). Our results show that optical-grade antimony sulfide (Sb₂S₃) can be deposited onto various substrates at subwavelength thicknesses. Notably, these films demonstrate non-volatile phase change modulation contrasts comparable to PVD methods, with significantly lower volatile thermo-optic response, promising enhanced performance by reducing noise and drift. The first reconfigurable phase change chalcogenide metasurface formed from solution-processed PCM films are also introduced, which can be patterned into polarization-sensitive subwavelength nanograting metasurfaces without degradation, allowing for period-dependent resonances and large modulation contrasts. The liquid nature of the deposition technique is perfectly suited for inclusion in display technologies and the integration of various emitters and active nanoparticles into PCM films, paving the way for new hybrid PCM composites, offering numerous solutions for emerging quantum and neuromorphic photonic platforms while lowering production costs.