Shift Selectivity and Hologram Playback Margin Dependence on the Average Speckle Size of a Randomly Phase Encoded Reference Beam

Abstract

Several important hologram reconstruction parameters of shift multiplexing with a randomly phase encoded reference beam were investigated as functions of the reference beam average speckle size at the medium. Those are shift selectivity, reference beam defocus margin, and medium tilt margin. It was confirmed that these parameters are linearly dependent on the average speckle size in certain directions. The exception was the in-track direction medium tilt margin which is dominated by the Bragg matching condition. We found that smaller average speckle size is preferable in view of achieving higher recording density, while larger average speckle size is desirable in view of having wider playback margins. Based on the experimental results, the multiplexing of 300 holograms per unit area was demonstrated with a polymer medium with sufficiently low bit error rates.