Selectivity and tolerance calculations with half-cone-shaped reference beam in volume holographic storage

Abstract

When developing a compact holographic storage system it is beneficial to use a reflection-type arrangement, where the entire optical system is on the same side of the storage material. For reflection type holographic discs, it is important to use half-cone-shaped spherical reference beams to avoid the ghost images caused by phase conjugate readout. The goal of this paper is to look for appropriate engineering tools to model diffraction efficiency of finite volume holograms created by half-cone-shaped reference beams. Two numerical methods -volume integral and beam propagation -were applied to calculate the shift selectivity curves. Simulation results show significant discrepancies between the shift selectivity curves corresponding to the approximated analytical equation and the numerically calculated shift selectivity curves; there are no Bragg zeros and there are no selective and nonselective directions. Beside the shift selectivity curves, track, focus, tilt and wavelength tolerance values are shown for finite volume holograms.

Comparison of Coaxial Holographic Storage Arrangements from the M Number Consumption Point of View

“…16,17) Inside the storage material, the beams for hologram writing and reconstruction processes are calculated by a scalar and fast Fourier transform (FFT)-based BPM. [8][9][10][11][12][13][14][15] Table I shows the main important parameters of the calculations. The diffraction efficiency of the reconstructed beam monotonically increases with the writing energy.…”