Voltage-Tunable Microhole-Structured Silicon Spectrometer

Abstract The intrinsically limited spectral encoding capability of conventional silicon photodiodes remains a major challenge for developing compact and energy-efficient voltage-tunable spectrometers. Engineering silicon microstructures to produce bias-dependent spectral responsivity offers a promising route toward electrically programmable spectral encoding within a single photodetector. Here, we demonstrate a compact voltage-tunable silicon microhole computational spectrometer with electrically tunable spectral responsivity over 420–900 nm. The device provides a responsivity tuning range of 0.004–0.759 AW–1 at 870 nm, achieves a spectral resolution of 2 nm over 570–585 nm, and occupies a volume of only 730 × 730 × 300 μm3. Numerical simulations reveal that the microhole structure enhances the spatial overlap between photocarrier generation and regions of strong electrostatic field through the synergistic interplay of optical field enhancement and electrostatic field modulation, thereby enhancing bias-dependent responsivity. Furthermore, computational reconstruction of spectra from the CAVE and TokyoTech datasets yields spectral fidelities exceeding 95% and 88%, respectively, while experimental reconstruction of a broadband light source further validates the device’s capability for broadband spectral recovery. This work highlights the promise of electrically tunable silicon photodetector-based computational spectrometers for low-cost, low-power, readily integrable, and highly compact spectral sensing.