Intrinsic temperature sensitivity of tilted fiber Bragg grating based surface plasmon resonance sensors

Li-Yang Shao,Yanina Shevchenko,Jacques Albert

doi:10.1364/oe.18.011464

Abstract

A miniature surface plasmon resonance sensor is fabricated from a gold-coated standard optical fiber with an in-core tilted fiber Bragg grating fabricated by UV exposure. The sensor has a measured refractive index sensitivity of 571.5 nm/RIU (refractive index unit) at constant temperature. We show here that the intrinsic temperature sensitivity of this device is reduced to less than 6.3 pm/degrees C (between 23 degrees C and 59 degrees C) when measurements are referenced to a core mode reflection resonance of the grating. This residual sensitivity is essentially that of the 50 nm thick deposited gold layer but it is bigger by one order of magnitude than the expected value (0.51 pm/degrees C) for a gold-water interface.

Highlights

Surface plasmon resonance (SPR) sensors have been widely used in refractive-index related measurements, including label-free bio-chemical sensing, because of their high sensitivity and real-time detection capability
Most SPR sensors are fabricated using variants of the original Kretschmann-Raether geometry [1], a bulk optics approach that uses a high index glass prism with a thin metal coating deposited on its base, and tunneling across the metal from a wave totally internally reflected inside the prism to excite the plasmon waves
While there are many papers dedicated to the understanding and calibration of the effect of temperature on SPR sensors [14,15,16], we present here for the first time an experimental measurement of the effect of the thermal properties of the metal coating itself on the temperature sensitivity of a fiber optic SPR sensor

Summary

Introduction

Surface plasmon resonance (SPR) sensors have been widely used in refractive-index related measurements, including label-free bio-chemical sensing, because of their high sensitivity and real-time detection capability. Most SPR sensors are fabricated using variants of the original Kretschmann-Raether geometry [1], a bulk optics approach that uses a high index glass prism with a thin metal coating deposited on its base, and tunneling across the metal from a wave totally internally reflected inside the prism to excite the plasmon waves. In this case, plasmon resonances are found by measuring a dip in the reflection spectrum off the base of the prism, corresponding to rays that are phase matched to the plasmon (or equivalently for the angular dependence of the reflection of monochromatic light). In the work reported here, the temperature sensitivity of our recently developed tilted fiber Bragg grating SPR sensor is studied in detail and shown to be reducible to a few pm per degree Celcius

Methods

Results

Conclusion