Coupling plasmon-waveguide resonance and multiple plasma modes in hyperbolic metamaterials for high-performance sensing

Abstract

A sensor based on plasmon-waveguide resonance (PWR) exhibits an impressive narrow linewidth and has attracted extensive attention in plasmon label-free sensing. However, the low surface electric field intensity limits the detection ability of biomolecules, where the refractive index changes are restricted at the sensor surface. In this study, we study the coupling of PWR and multiple plasma modes in a hyperbolic metamaterial (HMM), combining narrow line width and electric field enhancement advantages. The PWR-HMM sensor includes a gold film, lossless dielectric layer, and metal/dielectric multilayer HMM array composed of 2-layer Au/Al2O3 stacks. The evanescent field of PWR is used to excite multiple plasma modes in the HMM. The figure of merit of the proposed structure reaches 5417 /RIU owing to the existence of lossless dielectric layer, which is 11.7 times than the conventional gold film structure. The maximum bulk sensitivity of the PWR-HMM sensor was 43,000 nm/RIU. In comparison with PWR, the surface electric field intensity and the surface sensitivity of PWR-HMM increase by four and two times, respectively. Furthermore, comparing the sensing performance of the PWR-HMM sensor and PWR-nanoparticle (NP) sensor (coupling PWR and localized surface plasmon resonance), it was found that PWR-HMM has 20% higher surface sensitivity than the PWR-NP. A sensing mechanism coupling PWR and multiple plasma modes in the HMMs opens a gate to significantly improve the PWR sensors performance, which is expected to be used to resolve urgent issues in biological, medical and clinical applications.

Plasmonic Nanostructure Biosensors: A Review

“…Depositing a dielectric layer onto the gold film results in the observation of plasmon waveguide resonance (PWR). This phenomenon can be utilized for enhancing the performance of sensing [46,47].…”

Design of self-coupled plasmonic hyperbolic metamaterials refractive index sensor based on intensity shift

“…Small changes in the nearby external environment will be significantly amplified owing to SPR, which generates strong local electric field enhancement effect. Using this property, scientists can design various surface plasmon sensors via various observable effects caused by changes in the refractive index of the external environment, such as changes in light intensity [1,2], angle [3,4], wavelength [5][6][7], phase [8] and even polarization near the surface plasmon resonance [9]. Compared with conventional biosensing technology, surface plasmon sensors are sensitive, label-free, and operate in real-time, and have extremely important application in disease detection [10][11][12][13][14], food safety [15], and environmental monitoring [16].…”