Fig. 7: Investigation of multi-stage design.

a Schematic illustration of the multi-stage MEMS spectrometer and voltage modulation channels. b Calibration matrix of the 3-stage spectrometer. Reconstruction of dual-wavelength spectrum with or without denoising at different wavelength spacings of (c) 90 pm, (d) 85 pm, (e) 40 pm, and (f) 35 pm.