2015/12/23 by Srishti Garg, Garg, Srishti, Murugesan Venkatapathi +1
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Gold and Silver Nanoparticles Synthesis and Applications #Optics (physics.optics) #Orbital Angular Momentum in Optics #Plasmonic and Surface Plasmon Research
paper · pdf · doi:10.48550/arxiv.1512.07463
openalex publication_date 2015/12/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recently, the coupling of two different modes of a homogeneous plasmonic\nparticle and their sharply varying spectra were elucidated as Fano resonances;\nan 'interference' of two spatially orthogonal modes driving each other. On the\nother hand, the scattering (and extinction) cross-section of a non-absorbing\ndielectric particle is always the sum of the cross-sections of all mode\nnumbers; and this rules out any such Fano type interference between two\ndifferent mode numbers. So delectric particles exhibit an interference\nstructure in their extinction spectra only if it manifests in the individual\nmodes describing the scattered field of the particle. We show that in a\nall-dielectric core-shell particle such strong interferences in multiple mode\nnumbers can be attained, and notably even as a spectral region of transparency\nand directional scattering of incident light. Here interference between the\ncomplementary normal modes of the nanoshell and core regions can be realized\nfor each mode number, resulting in a sharp interference structure in the\nextinction of the particle. This manifests as spectral regions of\nminimal/maximal interaction with the incident electromagnetic field. Such\nspectral properties are significant for many applications where the\nnon-radiative losses of plasmonic structures are a liability. Note that this\nbehaviour is useful for optical antennas, cloaking materials and a quantum\nmechanical interpretation of this classical effect may be signicant for\nsingle-photon based applications.\n