Hybrid dual-comb interferometer with easily established mutual coherence and a very high refresh rate.

In this Letter, we propose a hybrid dual-comb interferometer (DCI) with a free-running mode-locked laser and an electro-optic frequency comb. The mutual coherence of this DCI is achieved by using an injection locking technique without any complicated phase-locking loops or post data processing algorithms. The proposed architecture is validated by resolving more than 10,000 comb lines of 250 MHz spacing with a refresh rate of 500 kHz. This combination of two kinds of optical frequency comb sources is suitable for wideband spectroscopic applications, where moderate spectral resolutions as well as high refresh rates are necessary.