Investigation of a Reflective Counter-Propagating Holographic Setup

Abstract

A reflective counter-propagating holographic setup for optical data storage is presented. The system makes efficient use of the laser light by using the reference beam to generate the signal beam. After passing through the holographic medium, the reference beam is sent onto a spatial light modulator that directs the modified reference beam back into the holographic medium, where it interferes with the original reference beam. Thus 100% of the available laser power can be used for the reference beam. Furthermore, a special random phase mask and a corresponding data page format are introduced. The phase mask has an improved alignment tolerance of AE0:5 pixels in contrast to a conventional binary phase mask that has a tolerance of only AE0:1 pixels. Moreover, the mask still improves the shift-selectivity and eliminates the strong intensity peak in the Fourier plane. We investigate the shift selectivity and compare experimental and simulated results that were obtained with a two-dimensional fast-Fourier-transform (2D-FFT) volume integral method.

Material Consumption and Crosstalk Characteristics of Different Holographic Storage Concepts

“…Since the BPM needs much less computation time than the 2D-FFT volume integral method, the BPM was used for the simulation of the plane wave and collinear setups. The excellent agreement of simulated shift selectivities with experimental data is shown in the publication by Knittel et al 10) 3. Results…”

Improvement of Storage Capacity Using Confocal Scheme in Reflection-Type Holographic Memory System with Speckle Shift Multiplexing

“…Reflectiontype holographic memory has advantages for the collinear setup with the transmission-type geometry in terms of material consumption and crosstalk noise characteristics. 9,10) Recently, a microhologram as a reflection-type hologram was investigated for volumetric bit-oriented memory. 11,12) The storage capacity of the reflection-type holographic memory system with speckle shift multiplexing is derived numerically using a holographic memory simulator on the basis of scalar diffraction theory.…”