Progress in Dual-Comb Absolute Ranging Methods for Large-Scale Metrology

The use of incremental laser interferometers as measurement standards in large-scale metrology is common, but these can easily result in interrupted light during the measurement process, significantly limiting the flexibility of measurements. Recently, high-precision absolute ranging methods using femtosecond optical frequency combs as light sources have rapidly advanced. In particular, the dual-comb asynchronous optical sampling absolute ranging method, which employs two femtosecond optical frequency combs with slight repetition frequency differences, facilitates absolute distance measurements over long ranges, with high accuracy and high update rates. This paper provides a detailed summary of the current progress in large-scale dual-optical comb absolute ranging, beginning with a review of large-scale laser absolute ranging and femtosecond optical frequency comb absolute ranging. To overcome existing limitations in large-scale metrology, we conducted in-depth research on the construction and optimization of dual-comb sources, the optimization of ranging accuracy, the design of ranging systems, and the verification of ranging performance. Lastly, we present future directions for the application of dual-comb absolute ranging in large-scale metrology.