Single-lens speckle interferometer of tangential micro-displacements of the scattering surface with a single illuminating laser beam

Abstract

Schematic solutions for lateral displacement speckle interferometers with a single laser beam illuminating a controlled scattering surface and interference of two wave fields scattered in different directions which can be superimposed in several ways have been developed. The simplest way, but with limited sensitivity to displacement, is a scheme with a single lens that reduces scattered wave fields in the image plane of the surface. A mathematical model of the interferometer is being developed based on diffraction transformations of wave fields in the optical system of the interferometer. It is necessary for numerical modeling of interferometer signals and studying the information properties of the signal. The purpose of the research was to develop the theory of the method and develop a mathematical model of the interferometer, to study its physical and metrological properties, in particular, to study the dynamics of the speckle structure and the interference structure of the speckle modulated interferometer signal with a tangential displacement of the scattering surface of the object. Experimental studies show that a single-lens speckle interferometer with correlation processing of a speckle-modulated interference image of a surface area with a tangential displacement uniform in direction and magnitude can serve as an effective high-precision measuring tool for monitoring and measuring such displacements with variable velocity in magnitude and direction. Recording a sequence of image frames allows to determine the law of displacement in time at a speed limited by the frame recording frequency.

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Lyudmila Aleksandrovna Maksimova
IPTMU RAS - Separate structural subdivision of FRC "Saratov Scientific Center of the Russian Academy of Sciences"
Russia

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