Improvement to holographic digital data-storage systems with random and pseudorandom phase masks

Area of Science:

• Optics and Photonics
• Data Storage Technologies
• Information Science

Background:

• Holographic data storage offers high density but faces challenges like interpixel cross-talk and noise.
• The nonlinear nature of hologram recording and object beam profiles significantly contribute to data degradation.
• Random phase masks are employed to mitigate these issues, but their effectiveness is debated.

Purpose of the Study:

• To analyze the effects of random phase masks on holographic data storage.
• To identify the primary sources of interpixel cross-talk and noise.
• To investigate methods for optimizing signal-to-noise ratio and data fidelity.

Main Methods:

• Analysis of nonlinear recording effects in phase holograms.
• Investigation of object beam profile non-uniformity impact.
• Experimental evaluation of different reference-to-object beam ratios.
• Testing of multilevel pseudorandom phase masks for noise suppression.

Main Results:

• Nonlinear recording and object beam non-uniformity are identified as major sources of interpixel cross-talk.
• Increasing the reference-to-object beam ratio reduces nonlinear effects but increases scattering noise.
• A six-level pseudorandom phase mask effectively suppresses interpixel interference and nonlinear noise.
• Experimental results show significant improvements in signal-to-noise ratio and efficiency with the six-level mask.

Conclusions:

• An optimal reference-to-object beam ratio is crucial for maximizing signal-to-noise ratio in holographic data storage.
• Multilevel pseudorandom phase masks are highly effective in reducing both nonlinear noise and interpixel interference.
• The use of a six-level pseudorandom phase mask leads to substantial improvements in holographic data storage performance.