Research

Two optical frequency combs with a slight difference in repetition frequency (Δfr) form a dual-comb light source. Dual-comb interference to multi-heterodyne interference in the frequency domain, yielding a set of radio-frequency (RF) comb teeth spaced by Δfr. This RF comb reflects the of the optical frequency comb. In the time domain, it corresponds to linear optical sampling, producing a set of interference signals with a refresh time of 1/fr. Dual-comb ranging utilizes one optical comb passing through a Michelson interferometer, while the other optical comb interferes with the returning light from each arm of the interferometer The time difference between the interference signals from the two arms of the interferometer is used to determine the time-of-flight of the optical pulses, thereby determining the optical difference to be measured.