Holograms The Size Of Billboards?

Developments to Watch

HOLOGRAMS THE SIZE OF BILLBOARDS?

PICTURE A 100-TIERED WEDDING CAKE WITH THE SIDES of each layer sloping slightly inward toward the bottom. If the cake is made of glass and the sides are coated with silver, you've got a stack of lenses that can be used to create holograms or focus X-ray lasers for production of superdense computer chips. That, anyway, is the concept behind a U.S. patent awarded late last year to Carl R. Amos, an independent inventor in Reston, Va.

Amos says holograms made with his device would be viewable from any angle, making them suitable for, among other things, billboards. He says that's because in forming the hologram, part of a laser beam coming through the bottom of the "wedding cake" fans out over a wide area. Walter M. Gibson, director of the Center for X-Ray Optics at the State University of New York at Albany, says Amos' system seems to be unique--but he can't vouch for how well it would work.EDITED BY PETER COY