Long distance measurement with sub-micrometer accuracy using a frequency comb laser

The invention of the femtosecond frequency comb (FC) laser has revolutionized the field of high-resolution spectroscopy, by providing very accurate reference frequencies in the optical domain, acting as a ‘frequency ruler’. Similarly, a frequency comb can be viewed as a ruler for distance measurement, which is based on the fact that the vacuum distance between subsequent pulses is known with the accuracy of the used time standard. We have recently demonstrated absolute distance measurements using a FC laser applying a cross-correlation technique [1], which was supported by a theoretical and a numerical study on the formation of cross-correlation in dispersive media [2,3].