Vortex annihilation to reduce phase singularities and resultant speckles in computer-generated holography

Area of Science:

• Optics and Photonics
• Digital Holography
• Image Processing

Background:

• Computer-generated holography (CGH) enables realistic 3D displays but suffers from speckle noise.
• Speckles in CGH are caused by random phase distributions and are linked to optical vortices.
• These optical vortices are difficult to manage under coherent illumination, degrading image quality.

Purpose of the Study:

• To propose and validate a novel strategy for suppressing speckles in CGH.
• To address the challenge of intractable phase singularities caused by optical vortices.
• To improve the visual quality of holographic displays by reducing speckle noise.

Main Methods:

• A vortex annihilation strategy is proposed, integrating optimization algorithms.
• Scalar and vector potentials of the object phase are calculated.
• An irrotational phase component is extracted by annihilating optical vortices with opposite handedness.

Main Results:

• The proposed method effectively extracts the irrotational phase component.
• Experimental validation demonstrates significant speckle suppression in holographic displays.
• The number of phase singularities was reduced by approximately 100 times for grayscale objects.

Conclusions:

• The vortex annihilation strategy is effective in reducing speckles in CGH.
• Extracting the irrotational phase component leads to a speckle-suppressed viewing experience.
• This technique offers a promising solution for high-quality holographic display applications.