Development of techniques and instrumentation for open-path gas measurements using quantum cascade lasers

A compact system to control the temperature and current parameters of a QC laser was designed and tested. The system was found to be similar to a commercially available one. Closed path cell measurements of acrolein gas was demonstrated. Techniques for open-path intrapulse gas measurements using quantum cascade lasers was explored. The of use of a QCL for long distance measurements is evaluated with pathlengths up to 2km. A method to provide range resolved gas measurements was also demonstrated. Four different methods for obtaining baseline measurements are proposed and evaluated. The developed techniques demonstrated open path absorbance measurements of 1.8 x 10 -3 was demonstrated, and is estimated to be able to measure absorbances down to 5.0 x 10-4.