Correlational Nonlinear Optical Femtosecond Laser Profilometer with Micrometer Spatial Resolution

Abstract

A new femtosecond correlation nonlinear optical profilometer with micron spatial resolution is proposed, in order to increase the measurement accuracy of the heterogeneity profile of a surface at a distance up to 1 km. The principle of operation of this profilometer is based on determining the distance to the scanned object by measuring the time interval between sequences of the base (probing) and reflected femtosecond laser pulses. Thereafter, the profile of a rough surface is reestablished by using the one-dimensional spatial distribution of second-harmonic radiation as the space-time coupling of the sequences of the probing and reflected pulses in a nonlinear crystal is restored. It was shown that the spatial resolution of the profilometer is no greater than 5 μm.