Fig. 3: Reconstructed single-photon spectra using DC-GIS.

a Continuous multi-heterodyne signal within 12.8 ms including multiple interferograms. b Time-domain dual-comb interferograms corresponding to different spectral encodings with a total duration of 0.64 ms; gray dashed lines are used to distinguish different interferogram periods. c Dual-comb interferogram with a duration of 5 μs. d Photon-counting signals for 0.64-ms, 6.4-ms, 64-ms and 640-ms measurement times. The zoom-in inset is the photon-counting signal with the 640-ms acquisition. e Comparison between normalized absorption signature of the gas-phase acetylene obtained by DC-GIS for 640 ms photon-counting time (red dots) and the simulated result from HITRAN database (blue line). The areas colored in pink, gray, yellow, and black represent the standard deviation intervals in photon-counting times of 0.64 ms, 6.4 ms, 64 ms and 640 ms, respectively. f Broadband dual-comb ghost imaging spectrum (red line) covering 1525–1540 nm. The blue line is the simulated spectrum from HITRAN for comparison.