Digitally encoded dual-narrowband photodetectors for secure optical wireless communication

Next-generation optical wireless communication requires photodetectors that offer both high spectral selectivity and strong security against interception. However, conventional broadband devices remain vulnerable to spectral crosstalk and eavesdropping. Here we show a digitally encoded dual-narrowband organic photodetector that intrinsically integrates optical filtering with algorithm-assisted encryption to enable secure, high-fidelity optical wireless communication. Operating without an external power supply, the self-powered device employs a Fabry-Pérot cavity with a carefully designed organic spacer Liq to achieve selective detection at wavelengths of 485 nm and 910 nm, along with an ultrafast response time of 440 ns. By combining chaotic encryption with hardware-level wavelength selectivity, our hardware-software co-design system achieves an ultra-low bit-error rate of 9.17 × 10^-5 at 1.25 Mbps while demonstrating strong resilience to eavesdropping and external interference. Furthermore, precise cavity engineering allows the dual-narrowband response to be extended into the short-wave infrared region (>1230 nm), offering a scalable route toward multi-wavelength secure transmission, high-resolution spectroscopy, and intelligent photonic networks.