All‐Optical Data Processing with Photon‐Avalanching Nanocrystalline Photonic Synapse

Abstract Data processing and storage in electronic devices are typically performed as a sequence of elementary binary operations. Alternative approaches, such as neuromorphic or reservoir computing, are rapidly gaining interest where data processing is relatively slow, but can be performed in a more comprehensive way or massively in parallel, like in neuronal circuits. Here, time‐domain all‐optical information processing capabilities of photon‐avalanching (PA) nanoparticles at room temperature are discovered. Demonstrated functionality resembles properties found in neuronal synapses, such as: paired‐pulse facilitation and short‐term internal memory, in situ plasticity, multiple inputs processing, and all‐or‐nothing threshold response. The PA‐memory‐like behavior shows capability of machine‐learning‐algorithm‐free feature extraction and further recognition of 2D patterns with simple 2 input artificial neural network. Additionally, high nonlinearity of luminescence intensity in response to photoexcitation mimics and enhances spike‐timing‐dependent plasticity that is coherent in nature with the way a sound source is localized in animal neuronal circuits. Not only are yet unexplored fundamental properties of photon‐avalanche luminescence kinetics studied, but this approach, combined with recent achievements in photonics, light confinement and guiding, promises all‐optical data processing, control, adaptive responsivity, and storage on photonic chips.