IGZO-based transparent optoelectronic synapse for stealth mode trajectory tracking and registration.

We report a transparent indium gallium zinc oxide (IGZO)-based optoelectronic synapse that exhibits strong persistent photoconductivity and tunable synaptic plasticity. The device, built on a quartz substrate with indium tin oxide electrodes, maintains over 70% transparency in the visible range, enabling stealthy operation. By modulating light duration, intensity, and frequency, we achieve key neuromorphic behaviors. A 3 × 3 device array further demonstrates trajectory tracking by mapping real-time ultraviolet illumination sequences. Notably, upon re-illumination, the device shows enhanced current, mirroring relearning in biological synapses. This work highlights the feasibility of IGZO-based synapses for next-generation transparent neuromorphic devices, providing new avenues for covert sensing for military purpose, interactive displays, and adaptive wearable electronics.