SBIR Phase II: A Spectroscopic THz Sensor for Mixed Gas Analysis and Air Pollution Monitoring

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is to create an economical, light‐weight, high performance Terahertz (THz) spectrometer to allow testing of air and fossil fuels for the presence of harmful compounds. A frequency domain THz spectrometer is capable of characterizing the different molecules and chemicals in a gas sample. Historically these spectrometers have been relegated to the laboratory because of their size and complexity but recent technical advancements have made it possible to build a spectroscopic THz sensor small enough and light enough to be flown on a consumer drone. The reductions in size and cost have opened the door to using THz sensors for emissions testing of ships entering U.S. waters or contaminant testing of fossil fuels at petroleum processing facilities. This is significant because the ability to analyze samples locally removes the time and expense of collecting and shipping potentially dangerous compounds (i.e. flammable compounds or pollutants) to a laboratory for analysis. It also allows detection and classification to occur on short notice and without the need to subject personnel to the local environment. The proposed project will produce the first article of a compact, battery operated, autonomously operating spectroscopic THz sensor capable of mixed gas analysis to parts per million sensitivities. It will be constructed predominantly from economical off‐the‐shelf fiber optic components in a novel highly compact, light‐weight form factor. In order to achieve the high sensitivities, the spectroscopic THz sensor will incorporate: high fidelity lasers from the telecommunications industry, custom designed and fabricated high efficiency, hermetically sealed photomixers, a folded, light‐weight, carbon fiber sample cell incorporating patented 3D printed mirror technology and a patented optical phase‐modulation technique that removes the effects of coherent detection. The instrument will first be employed for laboratory based measurements of sulfur-containing contaminants in gas flows. Upon the successful demonstration of the capabilities of the instrument, a first article will be used in initial testing and collaborative field work. Sales of a larger laboratory instrument based on the same technology will begin simultaneously. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.