Fig. 1: The proposed one-to-broadband diffraction-based spectrometer.

a Schematic of the operation principle from a monochromatic diffraction to a broadband diffraction, i.e., one-to-broadband diffraction. A broadband diffraction \({I}_{B}\) captured in-situ can be represented as a superposition of wavelength-dependent PSFs from a single-shot monochromatic diffraction \({I}_{m}\) at wavelength \({\lambda }_{m}\) times the corresponding power spectrum components \({\rm{\omega }}\left(\lambda \right)\) over full spectrum. The incident spectrum \({\rm{\omega }}\left(\lambda \right)\) can be reconstructed using adaptive Tikhonov regularization. b Geometry of the proposed diffraction-based spectrometer. c A photograph of the ultra-compact computational spectrometer developed based on the proposed principle, which is integrated into a tiny CMOS panel (10 mm × 10 mm in size)