Spherical self-diffraction for speckle suppression of a spherical phase-only hologram.

The spherical computer-generated hologram is inevitably suffered from the speckle noise since it is necessary to add random phase to the object to ensure the scattering characteristic of reconstructed image. The speckle noise seriously degrades the quality of reconstructed image especially for a spherical phase-only hologram (SPOH). In this paper, spherical self-diffraction iteration (SSDI) algorithm is proposed to suppress the speckle noise in the SPOH. The algorithm is based on spherical self-diffraction (SSD) model which is a special case of spherical back-propagation (SBP) model at limit condition. The correctness of SBP and SSD as well as the effectiveness of SSDI algorithm are verified by numerical simulations. Meaningfully, the proposed method significantly outperforms the conventional methods in speckle suppression performance and computing speed. As far as we known, models of SBP and SSD as well as conception of SSDI are firstly proposed and applied for speckle suppression of SPOH.