Nanophotonic hierarchical hologram: Hierarchical information processing and nanometric data retrieval based on nanophotonics

A nanophotonic hierarchical hologram works in both optical far-fields and near-fields, the former being associated with conventional holographic images, and the latter being associated with the optical intensity distribution based on a nanometric structure that is accessible only via optical near-fields. In principle, a structural change occurring at the subwavelength scale does not affect the optical response functions, which are dominated by propagating light. Therefore, the visual aspect of the hologram is not affected by such a small structural change on the surface, and retrieval in both fields can be processed independently. We propose embedding a nanophotonic code, which is retrievable via optical near-field interactions involving nanometric structures, within an embossed hologram. Due to the one-dimensional grid structure of the hologram, evident polarization dependence appears in retrieving the code. Here we describe the basic concepts, numerical simulations, and experimental demonstrations of a prototype nanophotonic hierarchical hologram with a nanophotonic code and describe its optical characterization.