In terahertz dual-comb spectroscopies (THz-DCSs), electrical time delay lines are utilized to replace the mechanical ones widely used in traditional terahertz time-domain spectroscopic systems (THz-TDSs). Due to the usage of electrical delay line, the sampling time is effectively prolonged and the consecutive terahertz pulses can be sampled continuously, which leads to the improvement of frequency resolution and makes it possible for THz-DCSs work in dual (frequency- and time-domain, FD and TD) operation modes. Here, a THz-DCS is established by using two repetition-frequency-locked femtosecond (fs) lasers with a slight repetition frequency difference. A spectrum analyzer is used to directly record the terahertz spectral data. Alternatively, the terahertz transient pulses are sampled and recorded, and the terahertz spectra are obtained by Fourier transforming the TD data. The experimental results show that the terahertz spectra acquired in FD and TD are in good agreement with each other. For the dual-mode THz-DCS, the wideband terahertz spectral information and the specified narrowband spectral information with high frequency resolution can be simultaneously acquired, which is helpful for searching sharp-peaked fingerprint spectral features in a broad terahertz frequency range.

在太赫兹双梳光谱仪（THz-DCSs）中，电时延线被用来代替在传统太赫兹时域光谱系统（THz-TDSs）中广泛使用的机械时延线。由于使用了电延迟线，有效延长了采样时间，并且可以连续采样连续的太赫兹脉冲，从而提高了频率分辨率，并使得THz-DCS可以在双频（频率和时间）下工作。域，FD和TD）操作模式。在这里，通过使用两个重复频率差很小的重复锁频飞秒（fs）激光器来建立THz-DCS。频谱分析仪用于直接记录太赫兹频谱数据。另外，也可以对太赫兹瞬变脉冲进行采样和记录，太赫兹光谱是通过傅立叶变换TD数据获得的。实验结果表明，FD和TD获得的太赫兹光谱彼此吻合良好。对于双模式THz-DCS，可以同时获取宽带太赫兹频谱信息和具有高分辨率的指定窄带频谱信息，这有助于在宽太赫兹频率范围内搜索尖峰指纹频谱特征。