Hybrid dual-comb emission spectroscopy based on soliton microcomb

Dual-comb spectroscopy enables spectral measurement with large bandwidth spanning tens of nanometers, but it is limited to measuring absorption spectra and has to trade-off spectral resolution versus acquisition frame rate set by the repetition rate. Here, to alleviate these restrictions, we innovatively propose and demonstrate a hybrid dual-comb emission spectroscopy featuring a spectral resolution of 0.63 pm, a frame rate of 1 MHz, and a measurement bandwidth of 13.6 nm, simultaneously. A mode-locked fiber comb is harnessed to interrogate emission spectral features with high resolution via optical Fourier transform and a soliton microcomb serving as a probe pulse implement parallel multi-point sampling to significantly increase the acquisition rate by nearly 3 orders of magnitude from 1 kHz to 1 MHz. We believe that chip-scale microcombs will make the fast and high-resolution emission spectroscopy presented here a powerful tool for widespread applications.