Double Narrow Fano Resonances via Diffraction Coupling of Magnetic Plasmon Resonances in Embedded 3D Metamaterials for High-Quality Sensing

We theoretically demonstrate an approach to generate the double narrow Fano resonances via diffraction coupling of magnetic plasmon (MP) resonances by embedding 3D metamaterials composed of vertical Au U-shaped split-ring resonators (VSRRs) array into a dielectric substrate. Our strategy offers a homogeneous background allowing strong coupling between the MP resonances of VSRRs and the two surface collective optical modes of a periodic array resulting from Wood anomaly, which leads to two narrow hybridized MP modes from the visible to near-infrared regions. In addition, the interaction effects in the VSRRs with various geometric parameters are also systematically studied. Owing to the narrow hybrid MP mode being highly sensitive to small changes in the surrounding media, the sensitivity and the figure of merit (FoM) of the embedded 3D metamaterials with fabrication feasibility were as high as 590 nm/RIU and 104, respectively, which holds practical applications in label-free biosensing, such as the detection of medical diagnoses and sport doping drugs.

Synthesis of AuAg/Ag/Au open nanoshells with optimized magnetic plasmon resonance and broken symmetry for enhancing second-harmonic generation

The cooperation of magnetic and electric plasmon resonances in cup-shaped metallic nanostructures exhibits significant capability for second-harmonic generation (SHG) enhancement. Herein, we report an approach to synthesize Au open nanoshells...

Magnetic plasmon resonances in nanostructured topological insulators for strongly enhanced light–MoS2 interactions

Magnetic resonances not only play crucial roles in artificial magnetic materials but also offer a promising way for light control and interaction with matter. Recently, magnetic resonance effects have attracted special attention in plasmonic systems for overcoming magnetic response saturation at high frequencies and realizing high-performance optical functionalities. As novel states of matter, topological insulators (TIs) present topologically protected conducting surfaces and insulating bulks in a broad optical range, providing new building blocks for plasmonics. However, until now, high-frequency (e.g. visible range) magnetic resonances and related applications have not been demonstrated in TI systems. Herein, we report for the first time, to our knowledge, a kind of visible range magnetic plasmon resonances (MPRs) in TI structures composed of nanofabricated Sb2Te3 nanogrooves. The experimental results show that the MPR response can be tailored by adjusting the nanogroove height, width, and pitch, which agrees well with the simulations and theoretical calculations. Moreover, we innovatively integrated monolayer MoS2 onto a TI nanostructure and observed strongly reinforced light–MoS2 interactions induced by a significant MPR-induced electric field enhancement, remarkable compared with TI-based electric plasmon resonances (EPRs). The MoS2 photoluminescence can be flexibly tuned by controlling the incident light polarization. These results enrich TI optical physics and applications in highly efficient optical functionalities as well as artificial magnetic materials at high frequencies.