Nanophotonic traceable memory based on energy-localization and hierarchy of optical near-fields

Optical near-field interactions allow energy localization at scales smaller than the diffraction limit of light. They also show hierarchical responses, meaning that optical near-fields exhibit different physical behavior at different scales. In this paper, by combining these properties of optical near-fields, that is, energy-localization and hierarchy, we present a novel traceable optical memory that records the event of memory access to each of the bits, which is useful in applications such as high-security information transfer. The basic principle is numerically demonstrated using a metal nanostructure.