title: Absolute distance measurement by dual-comb nonlinear asynchronous optical sampling.
abstract: A dual-comb nonlinear asynchronous optical sampling method is proposed to simplify determination of the time interval and extend the non-ambiguity range in absolute length measurements. Type II second harmonic generation facilitates curve fitting in determining the time interval between adjacent pulses. Meanwhile, the non-ambiguity range is extended by adjusting the repetition rate of the signal laser. The performance of the proposed method is compared with a heterodyne interferometer. Results show that the system achieves a maximum residual of 100.6 nm and an uncertainty of 1.48 μm in a 0.5 ms acquisition time. With longer acquisition time, the uncertainty can be reduced to 166.6 nm for 50 ms and 82.9 nm for 500 ms. Moreover, the extension of the non-ambiguity range is demonstrated by measuring an absolute distance beyond the inherent range determined by the fixed repetition rate.
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Haoyun
authors.initials: H
authors.lastname: Wei
authors.forename: Xuejian
authors.initials: X
authors.lastname: Wu
authors.forename: Honglei
authors.initials: H
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li