Abrupt phase change in graphene-gold spr-based biosensor

Abstract

The performance of surface plasmon resonance (SPR) sensors can be different depending on which characteristic of the SPR sensor the amplitude or the phase is monitored. The phase sensitivity strongly depends on the geometry and the optical properties of the system. The existence of sharp changes in the phase spectrum variations is found as the thickness of SPR-supporting gold (d g ) varies around a critical thickness (d c ). In addition, the simulation results indicate that the phase sensitivity is divided into two regions so that phase sensitivity S j for region  d d g c is greater than region d g >d c . It is demonstrated in condition of  d d g c the phase sensitivity has a strong jump when the sensing medium refractive index lies within a certain interval, while the amplitude sensitivity has a monotonic shape. The phase analysis from another aspect exhibits that the phase maximum difference Δj max towards the blank sample is sensitive to refractive index in a continuous interval. As a result, the phase detection interval is tunable by varying the gold thickness, which potentially is important for medical, biology and chemistry applications.

Comparative Study on Sensing Characteristics of Optical Surface Plasmon Resonance Sensors Using A Single LHM-Dielectric Interface: A Theoretical Study

“…For the study of such a structure optical response wavelength,  of the incident TM-polarized beam is fixed. Let us recall that the numerical method (TMM) is generally valuable to simulate optical properties determined on absorption (A)/reflectance (R) and transmittance (T) spectra [33], which obey to the relationship: A+R+T=1, emitted from Nmultilayer arrangements [2,34,35,36].…”

“…The fundamental property that characterizes the most nanostructured materials based SPR sensors, is the angular or spectral sensitivities to changes in RI of a tested medium in direct contact with the active material layer involved. Otherwise, shift implied from the change of sample RI in the resonance condition observable on the light reflected from a coupling configuration, has been evaluated in different dependencies [34,35,47,48]. Starting from the above selective conditions in terms of minimums of width and reflectance dip depth, let us identify separately the effect that implies the thickness, dD of the intermediate layer.…”

Improve sensitivity for the study of blood diseases by analysis of hemoglobin concentration using a graphene-coated SPR based biosensor

“…Mk named the characteristic matrix for the k-layer and related to the optical properties and the thickness of each layer (dk) where [21]:…”

“…The reflectivity (R) for incident light is represented as [13], [21]: M +M q q -M +r q = M +M q q + M +M q…”

LSPR of Nanoparticles Inside Strong Absorbent Medium

“…The peak and width values of the SPR absorption spectra are very sensitive to the variation of the sensing layer refractive index. As a result, this configuration can determine the chemical bonds formed between the molecules (for example, biomolecules BioMs) and the sensor (AgNPs). − …”