Single-photon dual-comb ghost imaging spectroscopy

Single-photon spectroscopy (SPS), utilizing a single-pixel binary detector, often statistically recovers “high-dimension” spectral information from “low-dimension” photon-counting signals with ultra-high sensitivity. Nevertheless, it has been a significantly long-standing challenge to achieve either high-speed or high-resolution spectral measurements under photon-deficient scenarios. This study proposes single-photon dual-comb ghost imaging spectroscopy (DC-GIS), which utilizes a mode-resolved dual-comb matrix to interrogate the sample and directly calculates the high-resolution spectrum from photon-counting signals in milliseconds through ghost-imaging method. The concept of single-photon DC-GIS has been examined by measuring the vib-rotational transitions of acetylene with a resolution of 125 MHz and a measurement time of 6.4 ms, and strain sensing based on fiber Bragg grating with an ultra-high sensitivity of 0.5 µε with femtowatt-level power per comb line. This approach, breaking the classic idea of SPS recovering spectra from statistic histogram of photon counts, brings the high-speed and high-resolution spectroscopy to cutting-edge researches of photon-scarce scenarios.