MASS-PRODUCIBLE MICROSCOPIC COMPUTER-GENERATED HOLOGRAMS - MICROTAGS

We have developed a method for encoding phase and amplitude in microsc opic computer-generated holograms (microtags) for security application s. An 8 x 8 cell phase-only and an 8 x 8 cell phase-and-amplitude micr otag design has been exposed in photoresist by the extreme-ultraviolet (13.4-nm) lithography tool developed at Sandia National Laboratories. Each microtag measures 80 mu m X 160 mu m and contains features that are 0.2 mu m wide. Fraunhofer zone diffraction patterns can be obtaine d from fabricated microtags without any intervening optics and compare favorably with predicted diffraction patterns. (C) 1996 Optical Socie ty of America.