Defocusing the recording material away from the Fourier plane is necessary to reduce the strong dc component and produce a more homogeneous object beam distribution in the hologram plane in volume holographic digital data-storage systems with amplitude-modulated data pages. However, content- addressable searching with defocused recording results in higher cross-correlation peak intensities. We present a method for performing a faithful content-addressable search in a defocused volume holographic data-storage system. A new dc-filtered content-addressable search method for defocused volume holographic data-storage systems with binary data pages is demonstrated. Both simulation and experimental results are presented. The experimental results show good discrimination capability and confirm the feasibility of the proposed technique.
© 2008 Optical Society of America
Optical Data Storage
Original Manuscript: July 3, 2008
Revised Manuscript: October 26, 2008
Manuscript Accepted: November 11, 2008
Published: December 17, 2008
Bhargab Das, Joby Joseph, and Kehar Singh, "Improved data search by zero-order (dc) peak filtering in a defocused volume holographic content-addressable memory," Appl. Opt. 48, 55-63 (2009)