Optical wavefields measurement by digital holography methods

The phase distortions arise due to the atmospheric turbulence, the experimental conditions or a low quality of the imaging system. They can seriously limit the resolution of the image. Phase distortions can be spatially dependent, which means that a linear space-invariant transfer function cannot completely correct all phase errors in the field of view. Computer holography can be used to access a complex-valued optical field from an object under coherent illumination after detecting interference of intensity between the object and the reference beams. In this work, we developed approaches to improve image sharpness to measure phase distortions in computer holography using the example of defocus measurement. Image enhancement algorithms use a nonlinear optimization procedure to determine and measure phase distortions to form a reconstructed image at a high resolution. Our work was focused on numerical modelling, developing algorithms and conducting laboratory experiment. (paper)