Fig. 4. Experimental testing results of the spectrometer.

a Reconstructed spectra for a series of narrowband spectral lines. The black dashed lines mark their center wavelengths. b Reconstructed spectra for dual spectral lines with a decreasing spectral spacing from 100 pm down to 10 pm, respectively. c Reconstructed spectra for three spectral lines at different wavelengths, with a spectral spacing of 10 pm between two of them. d Reconstructed spectrum for a continuous, broadband signal. e Reconstructed spectrum for a hybrid signal with both broadband and narrowband spectral components. The inset exhibit the reconstruction of the narrowband component. f Investigation regarding the reconstruction accuracy and computing time versus the number of sampling channels. g Measured transmission spectra of one specific sampling channel at different temperatures. The insets present the small spectrum redshift as the temperature rises.