Adaptive mixed-constraint Gerchberg-Saxton algorithmfor phase-only holographic display br

At present, spatial light modulators are incapable of modulating both the amplitude and phase of thewavefront simultaneously. Therefore, when a spatial light modulator is used for holographic display, it isnecessary to encode the complex amplitude of the object wave into amplitude-only or phase-only computer-generated-hologram. The phase-only holographic display has attracted much attention of researchers due to itscharacteristics of high diffraction efficiency and no conjugate image. However, current optimization algorithmsfor generating phase-only hologram have the problems of iterative divergence, slow convergence speed, and poorreconstruction quality, which is difficult to satisfy the requirements for high-quality holographic display. In thiswork, we propose an accurate adaptive mixed constraint Gerchberg-Saxton algorithm by constraining thefrequency bandwidth in the hologram plane and adaptively constraining the amplitude of the reconstructedimage in the image plane based on the angular spectrum propagation theory. Firstly, we use the angularspectrum propagation model without paraxial approximation to simulate the forward and backward propagationof the light wave for ensuring the accuracy of the wavefront propagation. Secondly, dividing the image planeinto signal area and noise area according to the spatial distribution of target image, and different adaptivefeedback strategies are set up for the two regions based on the optimized effect of the phase-only hologram. Theadaptive feedback strategy is established, which can accelerate the convergence speed of the proposed algorithmand enhance the hologram of freedom of the optimization. Finally, the frequency bandwidth constraint strategyis introduced in the hologram plane to optimize the edge pixels and compensate for the frequency informationloss of the phase-only computer-generated hologram, which improves the reconstruction quality of the hologram.After 100 iterations, the average correlation coefficient of the holographic reconstructed image of the proposedalgorithm is about 0.9857, and the average peak signal-to-noise ratio is about 31.02 dB. The correlationcoefficient and the peak signal-to-noise ratio of the reconstructed images of the proposed algorithm are betterthan those of the Gerchberg-Saxton algorithm with only frequency bandwidth constraint strategy, and theproposed algorithm has clearer texture and better display effect. The results of numerical simulations andoptical experiments show the feasibility and effectiveness of the proposed method. The proposed adaptive mixedconstraint Gerchberg-Saxton algorithm is a promising technology for high-quality holographic display

Automated summary

Currently, spatial light modulators are unable to simultaneously modulate both the amplitude and phase of the wavefront. As a result, when used for holographic display, the complex amplitude of the object wave needs to be encoded into amplitude-only or phase-only computer-generated holograms. The existing optimization algorithms for generating phase-only holograms have issues such as iterative divergence, slow convergence speed, and poor reconstruction quality, which do not meet the requirements for high-quality holographic display. In this study, an accurate adaptive mixed constraint Gerchberg-Saxton algorithm is proposed to address these problems and improve the hologram reconstruction quality.