Wavefront reconstruction with a reference-free digital CCD-registration of multispectral speckle-patterns

N. V. Petrov^a, V. G. Bespalov^a, M. V. Volkov<sup>b

a</sup> St. Petersburg National Research University of Information Technologies, Mechanics and Optics
^b V. A. Fock Institute of Physics

Abstract: A method for reconstructing the wavefront based on a set of speckle patterns formed by different wavelengths is presented. An iterative algorithm for solving an equation of wave propagation is extended to use the intensity distributions recorded in various planes of the volume speckle field. Both numerical models and experimental results are presented. Two different experimental techniques have been tested: recording three different RGB-intensity distributions to the sensor spectral channels at one shot and using a large number of wavelengths of supercontinuum radiation formed by photonic-crystal fiber. The first mentioned technique gives the advantage in the analysis of fast processes. the second approach has simple and rugged recording scheme with fiber optic elements and provides faster and more accurate convergence of the proposed method.

Keywords: phase problem, wavefront reconstruction, speckle, diffraction theory.

UDC: 535.42; 535.417

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