Rapid Chemical Vapor Detection Using Optofluidic Ring Resonators
The optofluidic ring resonator (OFRR) is a novel gas sensing technology platform. In an OFRR gas sensor, the OFRR interior surface is coated with a layer of vapor-sensitive polymer. The interaction between the polymer and the gas molecules flowing through the OFRR results in a change in polymer refractive index and thickness, which can be detected by the circulating waveguide modes supported by the circular cross section of the OFRR. Due to the excellent fluidics of a capillary, the OFRR is capable of detecting chemical vapors rapidly with very low sample volume. In addition, the OFRR is highly compatible with gas chromatography (GC) and is a promising platform for development of micro-GC (μGC) with unique multipoint, on-column detection capability. In this chapter, we will discuss the fundamental operational principles of the OFRR gas sensor, followed by examples of rapid detection of several representative vapor analytes. The development of an OFRR-based μGC system and its applications in explosive separation and detection will also be presented.
KeywordsPolymer Layer Ring Resonator Refractive Index Change Vapor Molecule Refractive Index Sensitivity
We acknowledge support from the National Science Foundation (ECCS-0729903). We would also like to thank Mr. Aaron Thompson from ICx Nomadics for helping setup the GC system at the University of Missouri and for the GC/MS data used in Fig. 6.14b.
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