Animated holograms could be controlled by standard computer graphics cards

Ars Technica : It is easy to create static three-dimensional holographic images by using a special diffraction device to control the constructive and destructive interference patterns of light. Making moving images is much more difficult because current approaches involve physically changing the structure of the diffraction device. Daniel Smalley of MIT and his colleagues have attempted to solve the problem by using an array of anisotropic leaky-mode couplers, which use audio waves to change the timing and direction of the light traveling through them. Because the couplers are placed in a closely packed array, it is easy to control the way in which the light passing through each coupler interferes with its neighbors. The couplers work with red, green, and blue light simultaneously, which ensures a true-color hologram, and can be polarized to remove any artifacts in the light. The researchers demonstrated their device using 40 channels, which they created at a cost of just $50. Commercial manufacturing would likely reduce the cost significantly. They have now moved on to a larger 1250-channel version. They expect that the largest cost of a holographic device using this technology would be the commercial computer graphics cards needed to output the images to a display.