High Q-Factor Hybrid Metamaterial Waveguide Multi-Fano Resonance Sensor in the Visible Wavelength Range

We propose a high quality-factor (Q-factor) multi-Fano resonance hybrid metamaterial waveguide (HMW) sensor. By ingeniously designing a metal/dielectric hybrid waveguide structure, we can effectively tailor multi-Fano resonance peaks’ reflectance spectrum appearing in the visible wavelength range. In order to balance the high Q-factor and the best Fano resonance modulation depth, numerical calculation results demonstrated that the ultra-narrow linewidth resolution, the single-side quality factor, and Figure of Merit (FOM) can reach 1.7 nm, 690, and 236, respectively. Compared with the reported high Q-value (483) in the near-infrared band, an increase of 30% is achieved. Our proposed design may extend the application of Fano resonance in HMW from mid-infrared, terahertz band to visible band and have important research value in the fields of multi-wavelength non-labeled biosensing and slow light devices.

Controlling photonic spin Hall effect by a symmetric hyperbolic metamaterial waveguide

We investigate the photonic spin Hall effect (PSHE) in a symmetrical hyperbolic metamaterial (HMM) waveguide, which is constructed as an HMM/metal/HMM sandwich structure. We consider both type {\uppercase\expandafter{\romannumeral 1}} and type {\uppercase\expandafter{\romannumeral 2}} HMM in the study. We confirm that the structure of alternating sub-wavelength of plasma and dielectric or the structure of embedding plasma into a host dielectric matrix can display effective dielectric, effective metal, type {\uppercase\expandafter{\romannumeral 1}} and {\uppercase\expandafter{\romannumeral 2}} HMM under different wavelength ranges and different plasma fill fraction. This enable us to simultaneously realize type {\uppercase\expandafter{\romannumeral 1}} and type {\uppercase\expandafter{\romannumeral 2}} HMM. We show that the reflectivity ration $\vert r_{s}/r_{p} \vert$, directly related to transverse shifts generated by PSHE, greatly depends on the type and the thickness of HMM. Moreover, we find that the horizontal PSHE shifts are enhanced several times, especially in type {\uppercase\expandafter{\romannumeral 1}} structure; while the vertical PSHE shifts are significantly suppressed in both type {\uppercase\expandafter{\romannumeral 1}} and {\uppercase\expandafter{\romannumeral 2}} structure. By making the effect of metal type and thickness analysis, we further show that the impacts of these two factors on PSHE shifts are mainly subject to HMM thickness.