Spoof polariton enhanced modal density of states in planar nanostructured metallic cavities

摘要

Spoof surface modes on nanostructured metallic surfaces are known to havetailorable dispersion dependent on the geometric characteristics of theperiodic pattern. Here we examine the spoof plasmon dispersion on an isolatedgrating and a grating-planar mirror cavity configuration. The spoof polaritondispersion in the cavity is obtained using the scattering matrix approach, andthe related differential modal density of states is introduced to obtain themode dispersion and classify the cavity polariton modes. The grating-mirrorcavity geometry is an example of periodically nanostructured metals above aplanar ground plane. The properties discussed here are relevant forapplications ranging from thin electromagnetic perfect absorbers to near-fieldradiative heat transfer.