Mid-infrared (MIR) spectroscopy is instrumental in addressing gas molecule-related environmental and ecological challenges. Especially, massively parallel sensing capability is critical to multi-species molecules analysis, enabling the demands for various MIR gas characterizations. However, real-time, high-accuracy parallel sensing for multiple gases remains a significant challenge due to the limitations in laser bandwidth and sampling speed. Here, we present a broadband MIR dual-comb spectrometer for the simultaneous detection of multiple greenhouse gases. This MIR spectrometer employs a scheme of difference frequency generation (DFG), directly producing a wide spectrum spanning 3.2–4.7 μm with over 300,000 comb-tooth-resolved frequency lines at a 100 MHz resolution. In addition, we demonstrated the parallel detection of four mixed gas molecules (CH4, C2H2, CO, and N2O), in which the absorptions were in excellent agreement with HITRAN database. This broadband MIR dual-comb spectrometer is promising to be integrated with only fiber devices and periodically poled lithium niobate waveguides, providing a high-precision, high-efficiency approach for massively parallel sensing in atmospheric or industrial monitoring.AI Voice