Complex photonic materials for cryptography, holograms and memories

Most of the time, in a nano-fabrication facility, the efforts of a researcher are devoted to optimising the fabrication process in order to avoid defects and obtain the best result in terms of precision and quality of the fabricated device. However, it is inevitable that during the sample fabrication, a variable intrinsic amount of disorder is introduced. This feature can be exploited to develop novel applications spanning different areas of optics. A perfect unclonable cryptographic system based on new integrated optical fingerprints chip is presented and a proof of concept is provided. The role of disorder at the nanoscale is further studied in the fabrication processes such as electron beam lithography and dry-etching. In this scenario, the randomness is the starting point to develop new technologies for structural coloration and holograms.