LaserSPECks: Laser SPECtroscopic Trace-Gas Sensor Networks - Sensor Integration and Applications

We introduce a novel laser spectroscopic trace-gas sensor platform, LaserSPECks that integrates recently developed miniature quartz-enhanced photoacoustic spectroscopy (QE- PAS) gas sensing technology. This universal platform uses infrared laser spectroscopy detect and quantify numerous gas species at part-per-million to part-per-billion (ppm-ppb) concentrations (Curl, 2002). Traditional gas sensing devices capable of the same sensitivity and specificity are several orders of magnitude larger in size, cost, and power consumption. Thus, high resolution gas sensing technology has been difficult to integrate into small, low-power, replicated sensors suitable for wireless sensor networks (WSNs). This paper presents the principles behind laser based trace gas detection, design issues, and outlines the implementation of a miniaturized trace-gas sensor from commerical-off-the-shelf (COTS) components. We report on an early prototype as a proof- of-concept for integration into WSN applications. We also describe a number of ongoing collaborations in utilizing the platform in air pollution and carbon flux quantification, industrial plant control, explosives detection, and medical diagnosis. Furthermore, we discuss experimental performance evaluations to examine general platform requirements for these types of sensors. The results of our evaluation illustrate that our prototype improves upon previous gas sensing technology by two orders of magnitude in measures of power consumption, size, and cost, without sacrificing sensor performance. Our design and experiments reveal that laser-based trace-gas sensors built from COTS can be successfully implemented and integrated within WSN nodes to enable a wide range of new and important sensing applications.