Analysis and Synthesis of Hierarchy in Optical Near-Field Interactions at the Nanoscale Based on Angular Spectrum

Optical near-fields exhibit different behavior at different scales, a unique feature that could be exploited in system applications. Here we theoretically analyze the hierarchical nature of optical near-field interactions based on the angular spectrum representation, which allows analytical treatment giving an intuitive picture of the localization of optical near-fields and representing the relevance/irrelevance in optical near-field interactions at different scales of observation in the sub-wavelength regime. Based on this analysis, we also show a systematic approach to design an array of oscillating electric dipoles by which the desired hierarchical properties, namely, independent amplitudes at different scales of observation are synthesized through optical-near field interactions. The results agree well with the numerical simulations and rigorous theoretical calculations.