Random phase-free computer-generated hologram

TL;DR

This paper introduces a simple, computationally inexpensive method for reducing speckle noise in computer-generated holograms by multiplying object light with virtual convergence light, improving image quality without complex algorithms.

Contribution

The paper proposes a novel, efficient technique that eliminates the need for iterative algorithms to reduce speckle noise in CGHs by using virtual convergence light.

Findings

Significant speckle noise reduction demonstrated in simulations.

Enhanced image quality in optical reconstructions.

Effective application in lens-less zoom-able holographic projection.

Abstract

Addition of random phase to the object light is required in computer-generated holograms (CGHs) to widely diffuse the object light and to avoid its concentration on the CGH; however, this addition causes considerable speckle noise in the reconstructed image. For improving the speckle noise problem, techniques such as iterative phase retrieval algorithms and multi-random phase method are used; however, they are time consuming and are of limited effectiveness. Herein, we present a simple and computationally inexpensive method that drastically improves the image quality and reduces the speckle noise by multiplying the object light with the virtual convergence light. Feasibility of the proposed method is shown using simulations and optical reconstructions; moreover, we apply it to lens-less zoom-able holographic projection. The proposed method is useful for the speckle problems in holographic applications.