Three-dimensional fluorescence imaging based on digital holography

Fluorescence imaging is one of the important tools for biological field. For three-dimensional (3D) visualization of the fluorescence, we present two approaches. One is the common-path off-axis incoherent digital holography using dual gratings on dual Fresnel lenses. The other method is the image recovery of a defocused 2D fluorescence image by using the defocused distance obtained from the 3D phase imaging by off-axis digital holography. For the image recovery, the fluorescence bead image is blurred by the spherical aberration and wave propagation by the defocused distance. Spherical aberration is eliminated by Zernike polynomial and the defocused distance is obtained by numerical refocusing from the phase measurement in an off-axis digital holography. Both techniques can be applied to biological imaging.