Improved data search by zero-order (dc) peak filtering in a defocused volume holographic content-addressable memory

Area of Science:

• Optical data storage
• Holography
• Information retrieval

Background:

• Volume holographic data storage (VHDS) systems require defocusing to manage DC components and improve beam distribution.
• Defocused recording in VHDS leads to higher cross-correlation peak intensities during content-addressable searching.
• This presents a challenge for accurate data retrieval.

Purpose of the Study:

• To develop a method for faithful content-addressable searching in defocused VHDS.
• To introduce and demonstrate a novel DC-filtered search technique for binary data pages in defocused VHDS.

Main Methods:

• Implementing a DC-filtering approach to mitigate issues caused by defocusing.
• Utilizing amplitude-modulated and binary data pages for testing.
• Conducting both computer simulations and experimental validation.

Main Results:

• The proposed DC-filtered method effectively addresses higher cross-correlation peaks in defocused VHDS.
• Simulations and experimental results demonstrate good discrimination capability.
• The technique proves feasible for practical application.

Conclusions:

• A DC-filtered content-addressable search method is effective for defocused VHDS with binary data.
• This technique enables accurate data retrieval despite defocusing challenges.
• The study confirms the viability of the proposed method for holographic data storage.