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26 June 1996 Dual-beam dual-frequency scanning laser radar for investigation of ablation profiles
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High-quality eye treatment needs sophisticated and accurate instrumentation for cornea profile measurement before and after laser ablation. Plastic PMMA specimens are in ordinary use for pre-operational adjustment of laser intensity distribution, supposed that the results of the cornea surface ablation and the ablation of the plastic surface are identical. We investigated dual-beam technique for path- difference measurement of two laser beams, reflected from two neighboring points of the surface to be measured. The beams are frequency shifted relative to each other. Interference in the plane of receiver gives differential frequency, its phase being dependent on path difference. Acousto-optical scanning results in 2D distribution of path difference. To get surface profiles, along-line videosignals undergo the mathematical operation of integration. The sensitivity of several nanometers was got to flat specimens. For convenience of image processing and visualization, TV type scanning is applied to laser beams.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vasyl V. Molebny, Ioannis G. Pallikaris, Leonidas P. Naoumidis, Gary W. Kamerman, Eugene M. Smirnov, Leonid M. Ilchenko, and Vadym O. Goncharov "Dual-beam dual-frequency scanning laser radar for investigation of ablation profiles", Proc. SPIE 2748, Laser Radar Technology and Applications, (26 June 1996);

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