Application of the fast-Fourier-transform-based volume integral equation method to model volume diffraction in...

Area of Science:

• Optics and Photonics
• Optical Data Storage
• Computational Physics

Background:

• Holographic data storage utilizes thick gratings for high-density information retrieval.
• Shift-multiplexing is a key technique for increasing storage capacity in holographic systems.
• Accurate simulation of diffraction is crucial for understanding and optimizing holographic storage performance.

Purpose of the Study:

• To numerically simulate diffraction on thick holographic gratings for shift-multiplexed optical data storage.
• To investigate the impact of spatial shifts in reference beams on diffracted light.
• To compare simulation results with existing analytical models.

Main Methods:

• Utilized volume integral equations within the first Born approximation to model diffraction.
• Employed a 3D fast Fourier transform (FFT) technique for efficient convolution integral evaluation.
• Developed a parallelized FFT code on a personal computer for a 51.2 micrometer thick grating.

Main Results:

• Calculated diffracted electric field and Poynting-vector distributions for shifted probe beams.
• Observed monotonic decrease in shift selectivity curves in all three directions, differing from analytical models.
• Found scalar and vector calculations yielded similar results (within 5%) for the specified numerical aperture and polarization.

Conclusions:

• The numerical simulation provides a more accurate representation of diffraction in thick holographic gratings compared to previous analytical methods.
• The observed shift selectivity characteristics are critical for optimizing data retrieval in shift-multiplexed holographic storage systems.
• The developed computational approach enables efficient analysis of holographic grating performance.