Noninvasive and real-time plasmon waveguide resonance thermometry.

Pengfei Zhang,Le Liu,Yanhong Ji,Yonghong He,Yanfei Zhou,Hui Ma

doi:10.3390/s150408481

Abstract

In this paper, the noninvasive and real-time plasmon waveguide resonance (PWR) thermometry is reported theoretically and demonstrated experimentally. Owing to the enhanced evanescent field and thermal shield effect of its dielectric layer, a PWR thermometer permits accurate temperature sensing and has a wide dynamic range. A temperature measurement sensitivity of 9.4 × 10−3 °C is achieved and the thermo optic coefficient nonlinearity is measured in the experiment. The measurement of water cooling processes distributed in one dimension reveals that a PWR thermometer allows real-time temperature sensing and has potential to be applied for thermal gradient analysis. Apart from this, the PWR thermometer has the advantages of low cost and simple structure, since our transduction scheme can be constructed with conventional optical components and commercial coating techniques.

Highlights

Temperature sensing is of importance in several fields [1], such as the microfluidic research [2], molecular interaction analysis [3] and clinical medicine [4]
We demonstrate that the plasmon waveguide resonance (PWR) thermometer does have the advantages of the surface plasmon resonance (SPR) thermometers, and permits accurate temperature sensing in a wide temperature range because it can be free of background thermo optic effect of the sensing structure and has an enhanced evanescent field
To suppress the deviation caused by the response non-uniformity of the CCD, a hundred adjacent rows in one image are averaged to acquire the angular spectrum measuring the samples flowing through corresponding area

Summary

Introduction

Temperature sensing is of importance in several fields [1], such as the microfluidic research [2], molecular interaction analysis [3] and clinical medicine [4]. The SPR thermometers permit noninvasive and real-time temperature sensing and have a simple sensor structure [11,12,13]. They have broad application prospect with the aim to provide an economical and convenient thermometer module based on the fact that the SPR sensors have been widely used for label-free refractive index (RI) related measurements [3,14,15,16,17]. Because of the background TO effect of metal film, the sensitivity of the SPR thermometers is usually limited to the level of 0.1 °C, which is achieved by using comprehensive analyses to measure the intrinsic temperature sensitivity [23]. The dynamic range is usually limited to about 10 °C achieved by using the angle interrogation [24] that has the widest dynamic range among four types of interrogations of the SPR sensors [25]

Methods

Results

Conclusion