SPECTRAL MULTILAYER AUTHENTICATION DEVICE

摘要

An authentication device (12) is disclosed which comprises a first layer of material (16), and a second layer of material (18) disposed over the first layer (16). The electromagnetic response characteristics of the first and second layers are selected such that when illuminated with specific electromagnetic radiation the spectral signature produced by the device (12) is dependent on the respective materials present in the first and second layers (16, 18) and the respective positions of the first and second layers. A corresponding method of authenticating an article is also disclosed.