Extremely narrow resonant linewidths in metal-dielectric heterostructures

Abstract

Plasmonic high-quality factor resonators with narrow surface plasmon resonance (SPR) linewidths are extremely significant for surface-enhanced Raman scattering, optical sensors, imaging, and color filters. Unfortunately, extensive research on narrowing SPR linewidths is mainly based on noble metal nanostructures that are restricted by intrinsic loss. Here, heterostructures consisting of metal and dielectric metaphotonics are experimentally designed and fabricated for elaborating SPR linewidths. The results demonstrate that the SPR linewidths can be narrowed by 66.7% relative to that of aluminum nanostructures. The resonant linewidths are directly shrunk due to the interaction between low loss in the semiconductor nanostructures and electromagnetic confinement in the metal counterparts. Meanwhile, the resonant wavelength governed by heterostructure configurations shifts from 600 to 930 nm. This work will pave an avenue toward controlling resonant linewidths of metal-dielectric heterostructures for numerous applications.