Boosting figures of merit of cavity plasmon resonance based refractive index sensing in dielectric-metal core-shell resonators

Tunable plasmonic effects arising from metal-dielectric nanorods

We have investigated the plasmonic effects in a two-dimensional periodic array of metallodielectric nanorods with and without the rotational angle, in which the integration of the localized surface plasmon resonance (SPR) and hollow plasmon resonance (HPR) properties is performed. Four patterns of nanostructures are investigated. We make use of the three-dimensional finite element method to obtain the simulation results, which demonstrate that the localized SPR and HPR in metallodielectric nanorods enhance the near-field intensity and increase the depth of the transmittance dip, providing an additional degree of freedom in the control of the light wave at the nanoscale. Numerical results show that the depth of the transmittance dip and sensitivity of case 1 and case 2 can be elevated to a value of 83.21% and 6.7 times, respectively, when the rotational angle of metal-dielectric nanorods varies from 0° to 90°. The sensitivity of case 3 and case 4 can be raised to the magnitude of 700-1091 nm/RIU (where RIU is the refractive index unit), and the characteristics enable the extensive applications for nanophotonic devices with high performance in a predictable manner.

Strong tunable absorption enhancement in graphene using dielectric-metal core-shell resonators

We theoretically investigate light absorption by a graphene monolayer that is coated on the outside of dielectric-metal core-shell resonators (DMCSRs). We demonstrate that light absorption of graphene can be greatly enhanced in such multi-layered core-shell architectures as a result of the excitation of the hybridized bonding plasmon resonance supported by the DMCSRs. We also demonstrate that the absorption enhancement in graphene can be easily tuned over a wide range from the visible to the near-infrared, and particularly the enhancement factor can be optimally maximized at any selective wavelength, by simultaneously varying the dielectric core size and the metal shell thickness. Our results suggest that the graphene-wrapped DMCSRs with strong and highly wavelength-tunable absorption enhancement in graphene could be attractive candidates for applications in graphene-based photodetectors and image sensors.