title: Sub-micron absolute distance measurements in sub-millisecond times with dual free-running femtosecond Er fiber-lasers.
abstract: We demonstrate a simplified dual-comb LIDAR setup for precision absolute ranging that can achieve a ranging precision of 2 μm in 140 μs acquisition time. With averaging, the precision drops below 1 μm at 0.8 ms and below 200 nm at 20 ms. The system can measure the distance to multiple targets with negligible dead zones and a ranging ambiguity of 1 meter. The system is much simpler than a previous coherent dual-comb LIDAR because the two combs are replaced by free-running, saturable-absorber-based femtosecond Er fiber lasers, rather than tightly phase-locked combs, with the entire time base provided by a single 10-digit frequency counter. Despite the simpler design, the system provides a factor of three improved performance over the previous coherent dual comb LIDAR system.
authors.affiliation: Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu, Taiwan.
authors.forename: Tze-An
authors.initials: TA
authors.lastname: Liu
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Newbury
authors.forename: Ian
authors.initials: I
authors.lastname: Coddington