Two-dimensional Reconfigurable Photodiode for In-Sensor Color Filtering and Spectral Logic

Wavelength-selective photodetectors are essential for applications such as hyperspectral imaging, biomedical diagnostics, and secure optical communication. Conventional photodetection systems typically rely on external filters or post-processing to resolve spectral information, leading to increased system complexity and data transfer overhead. Here we report a reconfigurable photodiode based on spatially patterned doped tungsten diselenide (WSe2), which exhibits two runtime switchable photodetection mode and a bidirectional wavelength-dependent conductance modulation across the visible spectrum. Under a broadband photodetection mode, the device exhibited a fast response and a high linear dynamic range of 72 dB. Meanwhile, under color-filtering mode, the device enables non-volatile and color-selective detection spanning from 445 to 780 nm, to experimently achieve the in-sensor spectral processing including color-based logic operations and object trajectory recognition within visible wavelength range. We further show its application in encrypted optical communication using chromatically encoded digit patterns, where the device selectively decodes spectral information via bias-controlled readout. Classification accuracies reach ~98.99% for red and 98.76% for green patterns using a standard convolutional neural network, highlighting the potential of this platform for hardware-level spectral-domain information processing with minimal computational load.