Surface Plasmon Resonance sensor showing enhanced sensitivity for CO_2 detection in the mid-infrared range

Sylvain Herminjard,Jean-Paul Pellaux,Andrea Crottini,Hans Peter Herzig,Lorenzo Sirigu,Milan Fischer,Tobias Gresch,Jérôme Faist,Eric Studemann

doi:10.1364/oe.17.000293

Sylvain Herminjard, Jean-Paul Pellaux + Show 7 more

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https://doi.org/10.1364/oe.17.000293

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Journal: Optics Express	Publication Date: Jan 2, 2009
Citations: 85	License type: cc-by

Affiliation: University of Neuchâtel, ETH Zurich

Abstract

We present the first optical sensor based on Surface Plasmon Resonance (SPR) operating in the mid-infrared range. The experimental setup is based on a Kretschmann geometry with Ti/Au layers deposited on a CaF(2) prism where light excitation is provided by a Quantum Cascade Laser (QCL) source. Evidence of SPR is presented and the sensing capability of the system is demonstrated by using CO(2) and N(2) mixtures as test samples. Due to the absorption of CO(2) at this wavelength, it is shown that the sensitivity of this configuration is five times higher than a similar SPR sensor operating in the visible range of the spectrum.

Highlights

Surface plasmon based optical sensors have attracted a great interest in the last 10 years mostly for biochemical or biomedical applications
We present the first optical sensor based on Surface Plasmon Resonance (SPR) operating in the mid-infrared range
The experimental setup is based on a Kretschmann geometry with Ti/Au layers deposited on a CaF2 prism where light excitation is provided by a Quantum Cascade Laser (QCL) source

Summary

Introduction

Surface plasmon based optical sensors have attracted a great interest in the last 10 years mostly for biochemical or biomedical applications. Refractive index variations in the probed optical medium are rapidly observed with surface-plasmon-based techniques providing a high sensitivity that is hardly achieved with other optical techniques [1]. Surface Plasmons (SP) are charge-density oscillations localized at the interface between a metallic film (active layer) and a dielectric surface [2]. Surface Plasmon Resonance (SPR) refers to the optical excitation of these charge-density oscillations. There are various methods that use different coupling devices between the incident light and the SP. Other coupling methods include the use of diffraction gratings [4] or optical fibers [5], which are more complex to design and realize

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