Single-detector black phosphorus monolithic spectrometer with high spectral and temporal resolution

The emerging bandgap-tunable black phosphorous (BP) is a promising material for a compact spectrometer. Here, we report a BP based single-detector monolithic spectrometer operated at broadband mid-infrared. We found that, compared to the spectrally tunable photoresponses of a dual-gate BP transistor, its first deviate to the electric field is more electrostatic-displacement sensitive. This photocurrent deviates as a function of the wavenumber, and electrical gating presents a neat diagonal matrix form, which enables reconstructing the light spectrum with unprecedented spectral and temporal resolutions of ∼2 cm⁻¹ and 2 ms, respectively. We accordingly demonstrated a dynamic on-chip molecular fingerprint analysis.