A Phase Sensitivity-Enhanced Surface Plasmon Resonance Biosensor Based on ITO-Graphene Hybrid Structure

Plasmonics - In this paper, a surface plasmon resonance (SPR) sensor based on the hybrid structure of silver (Ag)-indium tin oxide (ITO)-graphene is proposed and investigated. SPR biosensors are...     

Graphene-MoS2 Hybrid Structure Enhanced Fiber Optic Surface Plasmon Resonance Sensor

Plasmonics - In this paper, a fiber optic surface plasmon resonance sensor based on graphene-MoS2 hybrid structure is presented. The wavelength interrogation method is employed to analyze the...     

Enhanced Sensitivity of Surface Plasmon Resonance Phase-Interrogation Biosensor by Using Silver Nanoparticles

It is demonstrated that the sensitivity of surface plasmon resonance phase-interrogation biosensor can be enhanced by using silver nanoparticles. Silver nanoparticles were fabricated on silver films by using thermal evaporation. Sizes of silver nanoparticles on silver thin film can be tuned by controlling the deposition parameters of thermal evaporation. By using surface plasmon resonance heterodyne interferometey to measure the phase difference between the p and s polarization of incident light, we have demonstrated that sensitivity of glucose detection down to the order of 10⁻⁸ refractive index units can be obtained.     

Sensitivity Enhancement of Ag-ITO-TMDCs-Graphene Nanostructure Based on Surface Plasmon Resonance Biosensors

Plasmonics - The novel configuration of surface plasmon resonance (SPR) based on Ag-indium tin oxide (ITO)-transition metal dichalcogenides (TMDCs)-graphene hybrid structures is proposed for highly...     

Sensitivity of Optical Fiber Sensor Based on Surface Plasmon Resonance: Modeling and Experiments

In this paper, surface plasmon resonance curves of an optical fiber-based sensor were investigated. From an experimental and theoretical perspective, the response curves were analyzed and discussed. Precisely, such curves were calculated by modeling the analyte/metallic layer interface using a multilayer system, including the effects of roughness. Then, the experimental response curves observed in solutions with different refractive indices were compared to the simulated curves. Good agreement was obtained with respect to the resonance peak location and the shape of the curves. Consequently, these results enabled us to predict the ideal functioning conditions of the sensor, i.e., the working parameters corresponding to the best sensitivities of detection.     

Lifetime of Enhanced Graphene Surface Plasmon and Superstrate Sensitivity

Plasmonics - We investigated the field enhancement and lifetime of tuning surface plasmon in zero-thickness nanostructured graphene patches. The graphene surface plasmon (GSP) resonance mechanism...     

Visible-Light Photocatalytic Application of Hierarchical Au-ZnO Flower-Rod Heterostructures via Surface Plasmon Resonance

The semiconductor metal oxide, ZnO, is limited to application in photocatalysis because of large bandgap. Metallic nanostructures are utilized to enhance visible-light absorption and improve photocatalytic activity via surface plasmon resonance (SPR). In this work, through a facile thermal decomposition method, the Au nanoparticles (NPs) were successfully loaded on oriented hierarchical ZnO flower-rod (ZFRs) heterostructures, which have a higher areal proportion of exposed active (001) crystal faces. The results indicate that ZFRs are wurtzite phase grown along the [001] direction and the Au NPs spread on the surface of ZFRs in metallic form. It reveals that there is an electronic interaction between Au NPs and ZFRs, and more oxygen molecules are adsorbed on the surface of Au-ZnO flower-rod heterostructures (AZFRs). The AZFRs show a strong absorbance in visible region due to the SPR and enhance the separation of electron–hole pair, resulting in an improvement of photocatalytic activity under visible-light irradiation. During 80 min, the degradation efficiency of rhodamine B for AZFRs-20 is about 3.7 times as the pure ZFRs. Moreover, the AZFRs exhibit predominant photoelectrochemical properties, and the photocurrent can reach 1.2?×?10^?4?A. Finally, the as-prepared photocatalytic device composed of AZFRs based on indium doped tin oxide glass is convenient to recycle without centrifugation.     

Ultra-narrow-band Infrared Absorbers Based on Surface Plasmon Resonance

Due to the advantage of improving the sensing performance, narrow-band metamaterial perfect absorbers (MPAs) have attracted much attention in the sensor field. Here, we propose an ultra-narrow-band infrared absorber (UNBIRA) based on localized surface plasmon resonance. The peak absorption of the UNBIRA exceeds 99% with the full width at half maximum (FWHM) of 1.94 nm and 6.32 nm for transverse electric (TE) wave and transverse magnetic (TM) wave in 1.5–1.8 μm. The corresponding Q-factors for TE wave and TM wave are 817 and 266, respectively. When used as an infrared refractive index sensor, the sensitivity of UNBIRA is as high as 1632.5 nm/RIU for TE wave and 1647.5 nm/RIU for TM wave. Accordingly, the figure of merits (FOMs) of 816.2/RIU for TE wave and 260.7/RIU for TM wave are achieved. This UNBIRA possesses a simple geometry structure and an excellent sensing performance, implying a great potential for application of ultra-narrow infrared sensing or detecting.

     

Sensitivity Enhancement of Surface Plasmon Resonance Biosensor with 2-D Franckeite Nanosheets

Plasmonics - The sensitivity of a standard surface plasmon resonance (SPR) biosensor in angular interrogation is low. A unique 2-dimensional substantial heterostructure, franckeite/graphene layer,...     

Enhanced Photonic Spin Hall Effect with a Bimetallic Film Surface Plasmon Resonance

Plasmonics - The surface plasmon resonance (SPR) with the bimetallic film can achieve minimum reflectivity and higher evanescent field enhancement than the SPR configuration with the single gold...     

Optimizing the Tin Selenide (SnSe) Allotrope/Gold-Based Surface Plasmon Resonance Sensors for Enhanced Sensitivity

The 2D material tin selenide monolayer (SnSe) has attracted a lot of attention due to its excellent optoelectronic properties. This study focuses on the investigation of the potential improvement of the response of surface plasmon resonance (SPR) sensors by coating the gold layer with SnSe allotrope (α, δ, ε) monolayers. Using an optimization algorithm along with the transfer matrix method (TMM), we determined the optimal thickness of the gold layer as a function of the number of monolayers added to significantly increase the sensor’s response in terms of reflectivity and phase. With respect to reflectivity, sensitivity increased by 20% in comparison with the optimal bare gold structure, whilst with respect to phase, sensitivity was approximately two orders of magnitude greater than the bare gold structure. Our results demonstrate that SPR sensors modified with SnSe monolayers could be used in diagnostic applications where both high sensitivity and small concentration of analyte are required.

     

Novel and Sensitive Core-Shell Nanoparticles Based on Surface Plasmon Resonance

In this paper, a rough silver core-shell nanoparticle with strong electric field enhancement in the vicinity of a bumpy structure on the silver core-shell surface is reported. A dipolar plasmonic mode of the silver nanoshell is investigated by using the quasi-static approach and plasmon hybridization theory, which analytical results identify the electric field enhancement spectra in which the enhancement is optimized. As the silver shell thickness is small, the hot spots play an important role in the plasmonic field enhancement. In addition, the deposition of a rough silver shell can generate a stronger near-field enhancement near the silver surface which is more desirable than that of a smooth silver shell for sensitive detection based on SPR and surface enhanced Raman scattering (SERS). The plasmonic field enhancement of a bumpy silver core-shell nanoparticle permits the detection and characterization of bovine serum albumin (BSA) protein molecule and hemoglobin solution with a high sensitivity.     

Detection of Intermolecular Interactions Based on Surface Plasmon Resonance Registration

Methods for registration of intermolecular interactions based on the phenomenon of surface plasmon resonance (SPR) have become one of the most efficient tools to solve fundamental and applied problems of analytical biochemistry. Nevertheless, capabilities of these methods are often insufficient to detect low concentrations of analytes or to screen large numbers of objects. That is why considerable efforts are directed at enhancing the sensitivity and efficiency of SPR-based measurements. This review describes the basic principles of the detection of intermolecular interactions using this method, provides a comparison of various types of SPR detectors, and classifies modern approaches to enhance sensitivity and efficiency of measurements.     

基于波长寻址的表面等离子体共振传感技术

本文提出了基于光谱扫描技术的非机械扫描的表面等离子体共振(SPR)传感技术,采用白光为SPR激发光源,通过单色仪控制入射光的波长实现光谱寻址,在保证灵敏度和动态范围的同时,使系统在整个动态范围内具有较好的线性,简化了传感器结构。理论分析了光谱扫描SPR传感技术的灵敏度和动态范围,搭建了实验系统,并测量了不同浓度的酒精水混合溶液的SPR信号变化。结果表明:系统折射率测量范围为1.30-1.38,灵敏度可达3.1×105RIU。     

Electrically Tunable Fiber Optic Sensor Based on Surface Plasmon Resonance

The response of optical fiber surface plasmon resonance (SPR) sensor to potential is monitored in real time. The potential-induced reflectance of a gold-coated optical fiber SPR probe is dependent on potential step width and ionic strength. Wider potential step and stronger ionic strength are generally able to enhance the reflectance and accelerate the response time. The specifically adsorptive anion Cl^? provides a pronounced effect on a potential-dependent SPR probe. The exclusive contact of the SPR probe with anion Cl^? could significantly slow down the optical response. The work offers opportunities for optical fiber SPR probes to characterize the electrochemical application.     

U-Shaped Photonic Crystal Fiber Based Surface Plasmon Resonance Sensors

A surface plasmon resonance sensor based on a U-shaped photonic crystal fiber with a rectangular lattice has been designed through finite element method. The U-shaped fiber exhibits not only stronger mechanical strength but also better sensor performance than our previous scheme. The upper detection limit extends to higher analyze refractive index, 1.384, for phase interrogation. We introduce a ratio to evaluate the impact of higher order plasmonic mode. For wavelength modulation scheme, the parameter to describe the performance of a sensor is chosen to be the figure of merit, which can be up to 533.8[RIU^?1] around complete coupling condition.     

基于表面等离子共振的适配体传感器应用研究进展

基于表面等离子共振的适配体传感器是利用适配体进行高特异性、高灵敏度、高通量检测的新型生物传感器。我们在简要阐述适配体的筛选方法、偶联技术及适配体传感器工作原理的基础上,结合最新的研究结果,对基于表面等离子共振的适配体传感器在生物活性小分子检测、传染病检测、肿瘤标志物检测、食品安全监测等方面的应用研究进展进行了综述。     

Theoretical Study of Sensitivity and Localized Surface Plasmon Resonance of Ag-Dielectric Core-Shell Multi-layered Nanosphere

Localized surface plasmon resonances (LSPRs) of Ag-dielectric-Ag multi-layered nanoshell are studied by quasi-static approximation and plasmon hybridization theory. Absorption properties of multi-layered nanoshell with the silver core and nanoshell separated by a dielectric layer exhibit strong coupling between the core and nanoshell. The result shows absorption spectrum of LSPRS is influenced by the refractive index of surrounding medium, the dielectric constant of middle dielectric layer, the thickness of inner core radius and outer shell layer. LSPR shift of the longest wavelength \(\left |\omega _{-}^{-}\right >\) is red-shifted with increasing the inner core radius. It is interesting to find that longer wavelength \(\left |\omega _{-}^{+}\right >\) mode is mainly effected by the ratio constant of the surrounding medium refractive index ε ₄ to the middle layer dielectric constant ε ₂. \(\left |\omega _{-}^{+}\right >\) mode takes place a blue-shift with increasing inner core radius when ε ₂ > ε ₄, a red-shift when ε ₂ < ε ₄, and no-shifting when ε ₂ = ε ₄. However, the influence of dielectric layer radius to \(\left |\omega _{-}^{+}\right >\) mode shows the different property as that of increasing the inner core radius. The underlying mechanisms are analyzed with the plasmon hybridization theory and the distribution of induced charge interaction between the inner core and outer shell. In addition, the influence of core radius, middle dielectric layer radius and outer shell radius to sensitivity of Ag-dielectric-Ag multi-layered nanoshell are also reported, a higher sensitivity could be gotten by adjusting geometrical parameters. Our theoretical study could give an easy way to analyze properties of the core-shell nanosphere based on plasmon hybridization theory and the induced charge interaction, and usefully broaden the applications in nano-optics.