Multiplane imaging and depth-of-focus extending in digital holography by a single-shot digital hologram

Limited depth of field is the main drawback of conventional microscopy that prevents observation of thick semi-transparent objects with all their features in focus, only a portion of the imaged volume along the optical axis is in good focus at once. The paper presents a novel reconstruction algorithm to image multiple planes at different depths simultaneously and realize extended focused imaging. A shift parameter that accounts for the coordinate system's transverse displacement of the image plane at different depths is introduced in the diffraction integral kernel. Combination of the diffraction integral kernel with different shift values and reconstruction depths yields multiplane imaging resolution in a single reconstruction. Moreover an extended depth-of-focus method is also presented through modifying the proposed multiplane imaging algorithm. Description of the method and experimental results are reported.