Phase-sensitive silicon-based total internal reflection sensor

S Patskovsky,A V Kabashin,M Meunier

doi:10.1364/oe.15.012523

Abstract

A concept of phase-sensitive Si-based Total Internal Reflection bio- and chemical sensor is presented. The sensor uses the reflection of light from an internal edge of a Si prism, which is in contact with analyte material changing its index of refraction (thickness). Changes of the refractive index are monitored by measuring the differential phase shift between p- and s-polarized components of light reflected from the system. We show that due to a high refractive index of Si, such methodology leads to a high sensitivity and dynamic range of measurements. Furthermore, the Si-based platform offers an easy bioimmobilization step and excellent opportunities for the development of multi-channel microsensors taking advantage of the advanced state of development of Si-based microfabrication technologies.

Highlights

Refractive index (RI) of a physical or chemical substance is a fundamental parameter, which characterizes its optical properties and can give important information on its condition [1]
Such monitoring requires evanescent wave excitation, which can be achieved in total internal reflection (TIR) or Surface Plasmon Resonance (SPR) geometry
We show that the phase sensitivity in TIR geometry can be drastically improved by using Si-based TIR geometry

Summary

Introduction

Refractive index (RI) of a physical or chemical substance is a fundamental parameter, which characterizes its optical properties and can give important information on its condition [1]. Such monitoring requires evanescent wave excitation, which can be achieved in total internal reflection (TIR) or Surface Plasmon Resonance (SPR) geometry. Since SPR provided a higher reflectivity-based sensitivity due to essentially resonant nature of sensing response [3,4], it has been much more frequently used in biological and chemical sensing compared to TIR-based implementations [5,6].

Results

Conclusion