Speckle-reduced reconstruction of a single-shot hologram by multiple tip-tilt modulations

Speckle can be attenuated by averaging the reconstructed images of each sub-hologram or being filtered with different filters, at the expense of resolution. We propose a de-speckling method for a single-shot digital hologram while maintaining the resolution. Different tip-tilt phases are demonstrated to cause changes only for the speckle distributions of the reconstructed image. The speckle is attenuated by averaging these intensity images with different speckle distributions. The normalized contrast can be reduced to 0.56 by averaging only 20 different reconstructed images. When the averaged image is processed with block matching and 3D filtering, a further de-speckled image at a normalized contrast of 0.46 can be obtained with highly preserved resolution.