Dual-wavelength dual combs driven by harmonic and fundamental mode-locking compound for absolute ranging

For dual-comb ranging, maintaining the large nonambiguity range under high sampling speed is challenging, hence hindering the ultimate performance of dual-comb sources. Here, by unlocking the dimension of repetition rate, we have demonstrated single-cavity dual combs consisting of fundamental mode-locking and harmonic mode-locking (HML), with an exemplified repetition rate of 50.8 and 305 MHz, respectively. The dual combs exhibit comparable noise performance to conventional twin laser combs, i.e., characterized by the inherent asynchronous sampling magnification of hybrid pulses, the temporal drifts of HML are less than 50 ps within a 500 ms timing window, and the relative period jitter of the dual combs is 1.42 fs. Using the dual combs, we achieved absolute distance measurement under an update time of 0.1 ms at a nonambiguity range of 2.95 m. In particular, the ranging precision reaches 745 nm at 200 ms acquisition time. Our findings represent the first dual-comb ranging implementation using the HML, achieving enhanced sampling speed without compromising the nonambiguity range. The results show that complex multipulse dynamics can be manipulated for high-speed and high-precision metrological applications. Nevertheless, our findings may enhance the performance of other dual-comb-enabled applications such as pump-probe and spectroscopy.