Nanostructured plasmonic chips employing nanopillar and nanoring hole arrays for enhanced sensitivity of SPR-based biosensing

Nanostructured plasmonic sensor chips interrogated using the Kretschmann configuration for highly sensitive localized sensing.

Versatile Sensing Structure: GaP/Au/Graphene/Silicon

A versatile sensing scheme for gas and biomolecule detection has been proposed theoretically using optimized GaP/Au/Graphene/Silicon structures. A Gallium Phosphide (GaP) prism is used as a substrate in the proposed surface plasmon resonance based sensing scheme, which is designed to be in Kretschmann configuration. The thicknesses of different constituent layers have been optimized for the maximum values of the sensitivities of the gas and bio-sensing probes. To delineate the role of the silicon layer, sensing probes without a silicon layer have also been numerically modelled and compared. The present GaP/Au/Graphene/Silicon probes possess higher values of sensitivity for the detection of gas and biomolecules compared to the conventional SPR sensing probes reported in the literature.

Sensitivity Enhancement of a Graphene, Zinc Sulfide-based Surface Plasmon Resonance Biosensor With an Ag Metal Configuration in the Visible Region

A biosensor based on the modified Kretschmann configuration is proposed here. The sensitivity of the conventional prism-based sensor using angular interrogation is low. To enhance the sensor's performance, layers of zinc sulfide (ZnS) and graphene have been deposited over the metal layer. The angular interrogation technique is used to analyze the performance of the sensor. The thickness of the Ag metal has been optimized. The thickness of the Ag metal is taken as 50 nm because minimum reflectance has been achieved. With the combinations of the four layers of ZnS and one graphene layer, the maximum sensitivity attained is 305o/RU. Performance parameters such as detection accuracy, FWHM, and quality factor of the sensor have been evaluated as obtained as 0.33 deg-1, 3.05 deg, 100.7 RIU-1, respectively. The proposed sensor has potential application in the field of biochemical and biological analyte detection.

Спектральные характеристики наклонного отражательного интерферометра как сенсора показателя преломления

The paper presents simulation of the refractive index sensor of the analyzed liquid in the Kretschmann configuration based on an oblique reflective interferometer (RI) and its spectral properties for the first time. The principle of operation of this sensor is based on the effect of inverted surface plasmon resonance (ISPR). The sensitive structure is the metal-dielectric multilayer coating based on a nickel thin film in combination with non-quartewavelength dielectric layers. Modeling of the RI manufacturing process under oblique light incidence is described. Formulas for estimating the sensitivity and spectral width of the reflection maximum of ISPR are given, as well as the figure of merit. It is shown that due to the high quality factor, this type of sensor can have very large figure of merit (>10^3).

A Simple Simulation of Surface Plasmon Resonance in The Kretschmann Configuration Using Google Sheets

This article describes a simple numerical simulation of three-layer surface plasmon resonance (SPR) in the Kretschmann configuration. The calculation was performed in Google Sheets, a web-based spreadsheet environment that functions similarly to Microsoft Excel where it is easily accessible for students via the internet. Specifically, Fresnel’s equations were utilized to calculate the intensity of the reflected light for the p-polarized incident light on a three-layer system. The complex functions were utilized to plot the SPR curves. We examined the change of the resonance angle by the influence of the incident wavelength. The simulation was also performed for different thicknesses of the gold film layer. To demonstrate the sensitivity, we obtained the SPR curves with the variation of the refractive index in the sensitive medium. The SPR accuracy was analysed by comparing our obtained result with the published work. It is intended to incorporate into undergraduate instrumental analysis courses.

High Sensitive Chiral Molecule Detector Based on The Amplified Lateral Shift in Kretschmann Configuration Involving Chiral TDBCs

We investigate a high sensitive chiral molecule detector based on Goos-Hanchen shift (S) in Kretschmann configuration involving chiral TDBCs. Fresnel equations and the stationary phase method are employed to calculate S. Due to the interaction between surface plasmon polaritons and chiral TDBCs, S with chiral TDBCs are amplified at near the resonant wavelengths of chiral TDBCs. Our calculation results show that although the difference between the resonant wavelengths of left and right TDBCs is 4.5nm, the difference of S with chiral TDBCs (ΔS) can reach to 400 times as the incident wavelength in certain conditions, which can be easily observed in experiments. There is an optimal thickness of the metal film to realize the largest difference of S between Kretschmann configurations with left TDBCs and right TDBCs. We also find that the positions of the largest S for the structures with left TDBCs and right TDBCs do not overlap. Furthermore, we discuss the oscillator strength f, which is mainly determined by TDBC concentration. We find that our proposed detector is quite sensitive with f. By changing f from 0.008 to 0.014 with the step of 0.002, the change of ΔS is no less than 5 times of the incident wavelength (2.9μm). Our proposed structure is very sensitive and has potential applications in experiments.