Continuous electrical tuning of reflectivity using phase-change materials

Phase-change materials (PCM) have gained considerable interest in the photonics community as nonvolatile tunable materials for reconfigurable devices. Here, we experimentally demonstrate the continuous electrical control of the crystalline fraction of Ge2Sb2Te5 (GST) via voltage pulses in platinum micro-heaters. Using co-designed electrical micro-heaters and a simple optical stack of thin films, including GST, we demonstrate the programming of more than 50 distinct levels of optical reflection in the near-infrared, spanning a three orders of magnitude reflection modulation. This continuous electrically programmed phase transition is a promising strategy for PCM integration in industrial foundries and shows promise for individual pixel addressing in multi-level applications such as neuromorphic computing or spatial light modulators.