Review of optical techniques for protection of documents and other objects

Abstract

Some novel as well as known solutions and practical examples of application of quantum and wave optics technologies for optical security will be discussed. Absorption of photons can result in photothermodestruction, what is used for laser engraving. Absorbed photons may also evoke the luminescence. UV luminescence for protection of securities will be pointed out. Advantages of anti-Stokes IR luminescence will be presented as well. Wave optics phenomena like diffraction or interference, are practically used for construction of various types of optically variable devices for optical security. The protection by exploiting of interference phenomena in thin films will be pointed out, as well. The place of the discussed techniques in various security lines will be presented.