Spectrally resolved laser ranging with frequency combs.

The multiheterodyne beatnote between two frequency combs having pulses sliding one with respect to another is used to perform spectrally resolved ranging of diffuse reflectors at short distances. The sliding comb sources are generated using one mode-locked laser and a two-beam interferometer, but two properly controlled lasers could be used as well. A pseudo-random binary modulation of the pulses is used to increase the non-ambiguous range. Ranging with a spatial resolution of 21 cm and a spectral resolution of 10 cm(-1) over a 200 cm(-1) spectral range is demonstrated.