Voumard T, Darvill J, Wildi T, Ludwig M, Mohr C, Hartl I, Herr T
Opt Lett. 2022 Mar 15;47(6):1379-1382. doi: 10.1364/OL.448575.
Dual-frequency comb spectroscopy permits broadband precision spectroscopy with high acquisition rate. The combs' repetition rates as well as the mutual coherence between the combs are key to fast and broadband measurements. Here, we demonstrate a 1-GHz high-repetition-rate dual-comb system with high mutual coherence (sub-Hz heterodyne beatnotes) based on mature, digitally controlled, low-noise erbium-doped mode-locked lasers. Two spectroscopy experiments are performed with acquisition parameters not attainable in a 100-MHz system: detection of water vapor absorption around 1375 nm, illustrating the potential for fast and ambiguity-free broadband operation, as well as acquisition of narrow gas absorption features across a spectral span of 0.6 THz (600 comb lines) in only 5 s.
双频梳状光谱技术可实现具有高采集速率的宽带精密光谱测量。梳状信号的重复频率以及它们之间的相互相干性是实现快速宽带测量的关键。在此，我们展示了一种基于成熟的、数字控制的、低噪声掺铒锁模激光器的1千兆赫兹高重复频率双梳系统，该系统具有高相互相干性（亚赫兹外差拍频）。我们进行了两个光谱实验，其采集参数在100兆赫兹系统中无法实现：检测1375纳米附近的水蒸气吸收，这说明了快速且无模糊宽带操作的潜力，以及仅在5秒内获取跨越0.6太赫兹（600条梳状线）光谱范围的窄气体吸收特征。
