Single-photon level detection technique of long open-air path dual-comb spectroscopy

Optical frequency combs are important tools in the field of quantum precision measurement. Over the past decade, dual-comb spectroscopy technology has been widely applied in Earth sciences, especially in atmospheric laser remote sensing. It has demonstrated significant advantages in measurement accuracy and interference resistance compared to traditional laser remote sensing technologies. This work aims to address the key technical bottlenecks in current open-air dual-comb spectroscopy (DCS) technology for long-distance detection and non-cooperative target conditions, focusing on the application of single-photon weak signal detection technology in dual-comb spectroscopy. By introducing photon counting technology, we can achieve high-resolution spectral measurement under extremely low light conditions, significantly enhancing the detection capability of dual-comb spectroscopy. This work will conduct laboratory and field dual-comb spectroscopy experiments, focusing on the reconstruction of dual-comb interference spectra based on photon arrival times, precise spectral modulation and synchronization of optical frequency combs, and spectral processing and inversion algorithms. The research results will provide strong technical support for atmospheric science, environmental monitoring, and fundamental physics research, and are expected to promote the development of global atmospheric multi-element remote sensing technology.