Analytical model of SPR phase shift against refractive index

EasyChair Preprint no. 1333

Abstract

Surface plasmon resonance (SPR) is known for label-free, real-time and high resolution characteristics, rendering it a powerful biosensor. However, we face some problems when analyzing data. First of all, we cannot directly measure the refractive index change as a function of time, but we can measure the change of phase to time to know the mass change on the chip surface. Therefore, we need a transfer function (∆RI(∆ϕ)) to transfer the phase change to the refractive index change. Secondly, the relationship of the phase change and the refractive index change is in non-linear trends, so we cannot fit the result by single high power polynomial. Last but not least, SPR system works according to the Fresnel’s equations. However, in traditional analyzing methods, the Fresnel’s equations weren’t applied. Hence, we propose an algorithm (Fig.1) to obtain the transfer function and simultaneously solve the non-linear issue and fit the Fresnel’s equation. In this work, fitting the Fresnel model to the experimental data significantly declines the residual from the order of 10^-3 to 10^-5 (Fig.3).

Keyphrases: Fresnel’s equations, Phase sensitive surface plasmon resonance, polynomial fit

@Booklet{EasyChair:1333,
  author = {Yung-Hsiang Liao and Tzu-Heng Wu and Ching-Hsu Yang and Chii-Wann Lin},
  title = {Analytical model of SPR phase shift against refractive index},
  howpublished = {EasyChair Preprint no. 1333},

  year = {EasyChair, 2019}}