自适应双光梳光谱原理分析与实现

In this paper, partial P branch lines in the ν1+ ν3 absorption band of the acetylene are measured by the adaptive dual-comb spectroscopy sampling technique. The validity of the method is verified by comparison of the measured results with the standard absorption lines in HITRAN database. The mechanism of adaptive sampling technique based on the sampling theorem is analyzed. High-order features and bandwidth characteristics of the adaptive sampling techniques are further discussed. In the experiment setup, 200 nm super continuums are generated in nonlinear fiber, and then the wide spectra are extended. Partial absorption lines of the acetylene are retrieved from a 600 μs pulse signal in time domain with 1.09 GHz spectral resolution at a refresh rate of 180 Hz. The fast instabilities between combs are well compensated by the adaptive sampling technique under a room temperature environment. Meanwhile, with a 7.01 MHz stabilization accuracy of repetition rates, we suppress slow drifts effectively by further stabilizing the repetition rates of combs and tuning the center frequency of continuous-wave lasers. In this way, the stable running time of the dual-comb adaptive sampling system is increased from only a few minutes to more than half an hour, and thus the long-term stability and practicability of adaptive dual-comb spectroscopy are enhanced.