Tailoring the plasmonic Fano resonance in metallic photonic crystals

Nanophotonics

article

Christina Bauer¹  Harald Giessen¹ 

[1] 4th Physics Institute and Research Center SCoPE, University of Stuttgart

关键词: coupling strength;    Fano resonance;    photonic crystals;    plasmonic;    waveguide;   

DOI  :  10.1515/nanoph-2019-0335

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Periodically arranged metallic nanowires on top of a waveguide layer show a strong coupling between the particle plasmon of the wires and the waveguide mode. By introducing a dielectric spacer layer between the metallic structures and the waveguide layer, this coupling can be reduced. Here, the thickness of this spacer layer is varied and the coupling strength is determined for each spacer layer thickness by fitting an effective energy matrix to the energy positions of the resonance peaks. It is found that the coupling strength can be very well described by the electric field amplitude of the waveguide mode at the location of the nanowires. We carried out experiments and found very good agreement with theory and our simple model. Using this method, we achieved experimentally an extremely small mode splitting as small as 25 meV leading to very sharp spectral features. Our pathway and design for tailoring the coupling strength of plasmonic Fano resonances will enable the design of highly sensitive plasmonic sensor devices and open the door for narrow plasmonic spectral features for nonlinear optics and slow light propagation.

【 授权许可】

CC BY