Total funneling of light in high aspect ratio plasmonic nanoresonators

Abstract

We demonstrate the total extinction of the reflectivity for a transverse magnetic polarized wave on a gold surface etched on 6% of its area by both narrow (150 nm) and deep (2 μm) grooves. These high aspect ratio metallic grooves were fabricated using a mold cast technique based on an electrolytic growth of gold. They exhibit two resonance peaks corresponding to the first and second cavity modes inside the grooves. We also evidence the incidence-invariance of their spectral response, which undoubtedly shows the localized nature of the resonances. These experimental results confirm the prediction of total funneling of light in very narrow grooves.

Plasmonic Hybrid Cavity-Channel Structure for Tunable Narrow-Band Optical Absorption

“…When the channel modes are coupled with the horizontal surface plasmons, that is, when nodes are formed at the channel exits to block the power flow in the channel, the absorptance drastically increased to form a sharp coupled resonance mode. These closed channel resonance conditions, which are different from other reported channel modes [19][20][21], are supported by horizontal surface plasmons. Therefore, the closed channel resonance condition can only be controlled by changing the U-cavity parameters.…”

Plasmonics in the mid-infrared

“…Absorption can be increased by confining the dots in a waveguide structure and using a metallic grating coupler to couple the incident light into one of the waveguide modes. The third approach is to make deep subwavelength slots in the surface of a metal 19 . Coupling surface plasmons to the walls of the slots provides very high effective indices for the mode in the slot.…”

Dual-band near-infrared plasmonic perfect absorber assisted by strong coupling between bright-dark nanoresonators

“…It is obvious that the incident electromagnetic energy is strongly localized in the slit air groove, which leads to the ohmic loss within the silver walls. It should be noted that the funneling mechanism has no relationship with the propagation SPPs on grating surface, instead it originates from the interference between the incident wave and the evanescent field of resonant waves in the groove [22].…”