Embedding an optically-detectable pattern of information in an electrical element

An electrical element is fabricated including an optically-detectable pattern of embedded information. An initial physical design is received for an electrical element that performs an electrical function, together with a pattern of information to be embedded in the electrical element. An encoding region is designated within the initial physical design of the electrical element. Information-encoding patterns are determined for one or more thin-film layers in the encoding region to form an optical layer structure that encodes the pattern of information. The initial physical design and the information-encoding patterns are combined into a modified physical design which is used to fabricate the electrical element. The fabricated electrical element performs the electrical function and forms an optically-detectable interference image including the embedded pattern of information when illuminated by incident light.