Technique for modelling diffractive multi-phase holographic elements

摘要

It was proposed technique for modeling of adaptive diffractive elements in holographic system that based on a new method of wave equation solution analysis of the aperture diffraction problem. The method is based on new integral approach to modeling of laser beam diffraction on an arbitrary aperture by investigation of the singular wave component derived from a rigorous Sommerfeld's solution. Developed on the basis of proposed integral representation the effective algorithm is useful for providing analytical studying and numerical modeling the aperture diffracted field without paraxial approximation and the specific form of the convolution kernel that describes the diffraction with taking into account the size of cell allows alternative reconstruction procedure of diffraction pattern. The structure of the diffraction field not only in far zone but also in near and middle diffraction zone depending on profile of the amplitude-phase diffractive grating can be analysed. The extension of new method of modeling diffraction on amplitude-phase mask and possibilities of its practical application such as computer modeling of diffraction on a spatial light modulator (SLM), which consists of squared cells, for a wavefront reconstruction are considered. Conclusions regarding the possibilities the representation the arbitrary fields by using the discrete matrix of elementary diffractive aperture cell for enhancement of iteration algorithm of hologram synthesis and phase retrieval are arrived at. Proposed method for reconstructed images of computer-generated holograms (CGH) enables one to synthesize CGH's and simulate digital image processing techniques for 3D image reconstruction by kinoform. The result of computer simulations and optical experiments are presented.