Holographic memory readout with reduced speckle

A method of reducing speckle noise in an output image from a holographic memory, comprising the steps of:

• providing a stored image in the holographic memory, the holographic memory exhibiting a Bragg effect along a horizontal axis;
• providing a readout reference beam having a plurality of plane wave components, each of said plane wave components having the same angle along said horizontal axis, a unique angle along a vertical axis substantially perpendicular to said horizontal axis, and a unique temporal frequency;
• illuminating the holographic memory with said plurality of readout beam components;
• generating a plurality of coincident, aligned, and mutually incoherent reconstructions of said stored image at an output plane;
• and
• providing a detector at said output plane for detecting said plurality of image reconstructions as the output image and averaging coherent noise to reduce speckle in the output image.

A method of reducing speckle noise in an output image from an angularly multiplexed hologram of recorded images in a holographic memory exhibiting a Bragg effect along a horizontal axis, comprising the steps of:

• providing a readout reference beam having a plurality of plane wave components, each of said plane wave components having the same angle along the horizontal axis, a unique angle along a vertical axis substantially perpendicular to the horizontal axis, and a unique temporal frequency;
• illuminating the holographic memory with said plurality of readout beam components;
• generating a plurality of coincident, aligned, and mutually incoherent reconstructions of one of said recorded images at an output plane;
• and
• providing an output detector at said output plane for detecting said plurality if image reconstructions as the output image and averaging coherent noise to reduce speckle in the output image.