A Hybrid Iterative Algorithm of Amplitude Weighting and Phase Gradient Descent for Generating Phase-Only Fourier Hologram

Abstract

Reconstruction of target images from phase-only hologram (POH) has the advantages of high diffraction efficiency and no conjugate terms. The Gerchberg-Saxton (GS) algorithm is a classical algorithm applied to recover the phase, but it most likely stagnantes after a few iterations. This paper proposes a hybrid iterative algorithm of Amplitude Weighting and Phase Gradient Descent (AW-PGD) to generate a higher-quality POH. Firstly, the quadratic phase is used as the initial phase, zero-pads the periphery of the target image, and then multiplies the two to form the complex amplitude as the iterative initial value. During iteration, the amplitude of the reconstructed image is constrained by an adaptive dynamic exponential term in the signal region to improve the reconstruction accuracy, the constraint in the non-signal region is relaxed to reduce the computational effort at the same time; and the phase gradient descent technology is used to increase the iteration step and speed up the convergence. Finally, the target image amplitude is reconstructed based on the generated POH. The numerical simulation results show that the algorithm does not have a significant increase in time cost with better reconstruction quality than the GS, Weighted GS (WGS) and Adaptive Weighted GS (AWGS) algorithm.