Dual-comb spectroscopy, in which two synchronized mode-locked lasers are used as light sources of Fourier-transform spectroscopy, attracts much attention by its high spectral resolution and broad spectral bandwidth. However, there exists a trade-off between the spectral acquisition rate and the signal-to-noise ratio or the spectral bandwidth. Here, we overcome this trade-off by employing a mode-locked laser, whose repetition rate is rapidly modulated, together with a fixed-repetition-rate mode-locked laser. Specifically, we performed characterization of molecular vibrations through time-domain coherent Raman spectroscopy. In this demonstration, a high-spectral acquisition rate of 100,000 spectra/s was achieved with a broad bandwidth of 200 – 1400 cm-1.
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