Integrated waveguide absorbance optode for chemical sensing

Mar Puyol, Manuel Del Valle, Ignacio Garcés, Francisco Villuendas, Carlos Domínguez, Julian Alonso

Research output: Contribution to journalArticleResearchpeer-review

31 Citations (Scopus)

Abstract

A new type of absorbance-based optical sensor is presented. It is based on a chemical transduction membrane that acts simultaneously as the sensing element and as the light guiding medium. This membrane is inserted between two micromachined waveguides in a silica on silicon structure. Light propagates longitudinally through the membrane, which changes its spectral properties accordingly while interacting with the analyte. As the path length corresponds to the membrane length, not its thickness, high sensitivity can be achieved without an increase of the response time. This paper summarizes the design, the construction, and the validation results obtained with integrated waveguide absorbance optode (IWAO) prototypes. The main advantages of the reported optode are its simple configuration, high sensitivity, and versatility. Experimental results obtained with this IWAO, using a potassium-selective bulk optode, are shown and compared to those obtained with a conventional absorbance device incorporating the same membrane. The optimum membrane thickness of 4 μm gave the lowest light losses (15 dB). The absorbance sensitivities obtained (-0.86 AU/decade) were, as expected, higher than those shown by the conventional device (-0.03 AU/decade), with comparable response times (t90% = 0.5 min).
Original languageEnglish
Pages (from-to)5037-5044
JournalAnalytical Chemistry
Volume71
Issue number22
DOIs
Publication statusPublished - 15 Nov 1999

Fingerprint Dive into the research topics of 'Integrated waveguide absorbance optode for chemical sensing'. Together they form a unique fingerprint.

Cite this