Reconfigurable Multistate Optical Memory in Mixed Halide Perovskites

The von Neumann bottleneck presents a growing challenge for the emerging prominence of data-intensive computing, such as large language model training. Optical memory in materials that could also perform computation offers a promising solution. Here, we report a reconfigurable multistate optical memory based on mixed halide perovskites (MHPs), leveraging their dynamic ionic behavior under femtosecond pulsed excitation. We find that the photoluminescence (PL) emission wavelength encodes excitation parameters as volatile, rewritable memory states. These states exhibit long-lived retention and can be rapidly erased via thermal pulses. By tuning excitation power and repetition rate, we achieve precise control over the PL wavelength, enabling analog-like synaptic behavior. Spatially resolved writing of multiple states within a single film highlights the potential for high-density memory. Our findings position MHPs as active photonic materials capable of storing and processing optical information, offering a path toward a scalable platform for low-power, high-bandwidth memory and neuromorphic computing.