UV-Visible-NIR Miniaturized Spectrometer Based on InSe/GaN Heterojunction.

Miniaturized spectrometers are critical for the development of next generation, highly integrated sensing systems. Conventional designs rely on bulky optical components, which restrict both device miniaturization and integration density. Computational spectral reconstruction has recently emerged as a promising strategy by eliminating optical dispersive elements and exploiting the intrinsic resolution of detector responses. Here, we report a miniaturized single-detector computational spectrometer based on a mixed-dimensional InSe/GaN heterojunction, which achieves spectral sensing and reconstruction across the 300-960 nm wavelength range within a compact footprint of 30 × 30 µm2. Additionally, it enables quantitative estimation of incident light power density in representative UV, visible, and NIR regions. We further validate its utility in imaging and bioinspired tetrachromatic vision tasks, highlighting its ability to perceive and reconstruct spectral information beyond the visible range. These results establish an effective pathway toward compact broadband computational spectrometers.