Absolute Distance Measurement Using Optical Sampling by Cavity Tuning

We propose here an interferometric method for absolute distance measurement using optical sampling by cavity tuning. The cross correlation patterns can be obtained by constantly changing the repetition frequency of a femtosecond pulse laser, and the distances can be determined by the instantaneous repetition rate of the peak of the interferogram. Our experimental results show agreement within 10 μm, corresponding to a relative precision of 2 × 10
^-7
in a range up to 47 m, compared with an incremental distance meter.