Nanophotonic code embedded in embossed hologram for hierarchical information retrieval

A 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 nearfields. 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 results in fabrication of a prototype hierarchical hologram and describe its optical characterization.