The modified Gerchberg-Saxton algorithm for subwavelength resolution holographic image with speckle suppression

The Gerchberg-Saxton algorithm is widely recognized as one of the most popular methods for calculating phase-only holograms. However, due to bandwidth limitations, this iterative method is not suitable for designing subwavelength resolution holograms. To address this challenge, we have modified the angular spectrum method (ASM) by incorporating additional information to compensate for lost high-frequency details in inverse propagation. In order to mitigate optical speckle artifacts that arise in the computational process, we have integrated the double amplitude freedom (DAF) into our approach. Furthermore, we have implemented a narrow probability distribution in the initial phase mask as a key strategy to minimize fluctuations in the intensity of the reconstructions. Our proposed method has successfully achieved subwavelength resolution reconstructions with reduced speckle noise.