SPR-based infrared detection of aqueous and gaseous media with silicon substrate

¹  Mediterranean Technology Park - Carrer de la Coruna, 13, 08860, Castelldefels, Barcelona, Spain
²  Jacob Ruisdaellaan 3, 5581 JK, Waalre, The Netherlands

Corresponding authors: rajaniitd@gmail.com anujsharma@gmail.com

Received: 26 April 2009
Accepted: 18 June 2009

Abstract

A high-accuracy surface plasmon resonance (SPR) sensor with silicon substrate and Al-Au bimetal is proposed for aqueous and gaseous detection in infrared (IR) with a single probe. Angular interrogation method is used for SPR excitation using infrared source in the Kretschmann-Reather configuration. Sensor's performance is analyzed in terms of intrinsic sensitivity (IS) that includes the width and shift of SPR curve for given refractive index of sensing medium. In a broadband IR range of 1200 nm (700 nm–1900 nm), the IS of the Al-Au bimetal-based silicon sensor is almost 350% more as compared with an Au-based one, which is the most widely used SPR active metal. The oxidation problem of the Al-based SPR sensor has been addressed. The physical explanation related to the results has been provided. Further, the performance of the proposed sensor design is better for gaseous sensing as compared to liquid sensing.