What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the...

Area of Science:

• Optics and Photonics
• Digital Holography
• Diffractive Optical Elements (DOEs)

Background:

• Fast reconstruction of holographic and diffractive optical elements (DOEs) is achievable with binary digital micromirror devices (DMDs).
• The inherent two-positional nature of DMD micromirrors necessitates the synthesis of binary DOEs.
• Existing methods for synthesizing amplitude binary inline Fresnel holograms in divergent beams require optimization for improved reconstruction quality.

Purpose of the Study:

• To investigate and improve the synthesis method for amplitude binary inline Fresnel holograms generated using DMDs in divergent beams.
• To compare various binarization techniques for enhancing the quality of reconstructed holographic and diffractive optical elements.
• To evaluate the performance of improved methods against the standard Otsu binarization technique.

Main Methods:

• Modified Gerchberg-Saxton algorithm combined with a direct search random trajectory technique.
• Comparative analysis of multiple binarization methods, including local and global thresholding techniques.
• Numerical simulations and optical experiments utilizing a digital micromirror device (DMD) for hologram synthesis up to 1024x1024 pixels.

Main Results:

• Local and several global thresholding methods demonstrated superior performance in hologram reconstruction compared to Otsu binarization.
• Significant improvements in reconstruction quality, evidenced by a 46% enhancement in Mean Squared Error (MSE) and Structural Similarity Index Measure (SSIM) values.
• A notable increase in diffraction efficiency by 27% was achieved with the optimized binarization methods.

Conclusions:

• Optimized binarization strategies, particularly local and global thresholding, offer substantial improvements for synthesizing binary DOEs with DMDs.
• The enhanced synthesis method leads to higher fidelity reconstructions and increased energy efficiency in holographic applications.
• This research provides a pathway for more effective utilization of DMDs in generating high-quality diffractive optical elements.