Specialized iterative optimization for a speckle-reduced amplitude-only hologram

Speckle noise constrains the performance of holographic three-dimensional (3D) display, highlighting the need for hologram optimization. In this paper, we propose a specialized iterative optimization method for speckle-reduced amplitude-only hologram (AOH). By integrating the single-sideband filtering principle with the angular-spectrum theory, the conjugate term of AOH can be directly separated during propagation, eliminating the need for additional filtering while reducing computational load. The specialized optimization applies the process repeatedly, imposing constraints in both spatial and frequency domains, termed single-sideband angular spectrum iteration. This method enhances the efficiency of AOH optimization and significantly mitigates speckle noise interference. Simulation results demonstrate that the PSNR of reconstructed images doubled, with optical experiments validating the effectiveness. Compared to conventional AOH, our approach achieves 3D reconstructions with superior image quality. It is anticipated that this method will facilitate the future application and advancement of speckle-free, amplitude-modulated holographic 3D display.