Enhanced rotational Bragg selectivity by use of random phase encoding in volume holographic filter.

An out-of-plane angular detection scheme with random phase encoding is proposed. A ground glass is attached on a rod, which is rotated around a center point, so that the rotation of the rod induces the displacement of the ground glass in a circular path. To enhance the rotational sensitivity we adjust the Bragg selectivity of the volume holographic optical element encoded by random phase. Therefore, the rotational sensitivity can be tuned over a large range from several degrees to ten thousandth degrees by changing the radius of rotation. The theoretical calculation, as well as experiment, is demonstrated.

Point spread function of a collinear holographic storage system.

A paraxial solution to the coaxial holographic storage algorithm is proposed based on the scalar diffraction theory and a VOHIL model (volume hologram being an integrator of the lights emitted from elementary light sources), which can give insight into the optical characteristics of the collinear holographic storage system in an effective way, including the point spread function and shift selectivity. The paraxial solution shows that the reference pattern is the key issue in the point spread function. Thus, the bit error rate of the system can be improved by changing the reference pattern. The proposed solution will be useful in the design of a new reference pattern to perform a high-quality readout pattern in the coaxial holographic storage system.

Enlarging multiplexing capacity with reduced radial cross talk in volume holographic discs.

A novel design for a volume holographic optical disc to reduce radial cross talk is proposed. By adopting a proper spatial filter, the radial cross talk can be reduced and the radial selectivity increases so that the multiplexing capacity can increase effectively. The theory and the corresponding experiment are demonstrated.

One-dimensional optical imaging with a volume holographic optical element.

We propose a novel imaging structure based on a volume holographic optical element that allows one-dimensional optical imaging through a specific Bragg window. The lateral magnification is shown to be linear and negative. Lateral magnifications of 2.5, 5, and 10 of the imaging element are demonstrated theoretically and experimentally.