Tunable Micro Cat's Eye Array in an Optical Identification System and Comparison of Different ID Tags

An optical identification (ID) system has been built, and dynamic ID tags are compared, which include a home-made tunable cat's eye retroreflector array, a liquid crystal (LC) spatial light modulator (SLM) combined with a retroreflective tape, a LC SLM combined with a plane mirror, and a LC SLM combined with normal white paper. Performance comparisons indicate that the tag implemented with the microtunable cat's eye retroreflector array offers the best system security. The image produced by the ID tag is also accurately recognized by the identification system.