A Step toward Holographic Videoconferencing - Technology Review

A Step toward Holographic Videoconferencing - Technology Review: "By improving the materials used to make the display and the optical system used to encode the images, they have now demonstrated a full-color holographic display that refreshes every two seconds. This work is described today in the journal Nature.

The key to the technology is a light-responsive polymer composite layered on a 12-inch-by-12-inch substrate and sandwiched between transparent electrodes. The composite is arranged in regions called "hogels" that are the holographic equivalent of pixels. Writing data to the hogels is complex, and many different compounds in the composite play a role. When a hogel is illuminated by an interference pattern produced by two green laser beams, a compound called a sensitizer absorbs light, and positive and negative charges in the sensitizer are separated. A polymer in the composite that's much more conductive to positive charges than negative ones pulls the positive charges away.

This charge separation generates an electrical field that in turn changes the orientation of red, green, and blue dye molecules in the composite. This change in orientation changes the way these molecules scatter light. It's this scattering that generates a 3-D effect. When the hogel is illuminated with light from an LED, it will scatter the light to make up one visual point in the hologram."