We present experimental demonstration of a new chemical sensing technique based on intracavity absorption in an external cavity quantum cascade laser (ECQCL). This new technique eliminates the need for an infrared photodetector and gas cell by detecting the intracavity absorption spectrum in the compliance voltage of the laser device itself. To demonstrate and characterize the technique, we measure infrared absorption spectra of chemicals including acetone and Freon-134a. Sub-ppm detection limits in one second are achieved, with the potential for increased sensitivity after further optimization. The technique enables development of handheld, high-sensitivity, and high-accuracy trace gas sensors for in-field use.

Date Published: 29 May 2013
PDF: 7 pages
Proc. SPIE 8726, Next-Generation Spectroscopic Technologies VI, 87260D (29 May 2013); doi: 10.1117/12.2015858

Published in SPIE Proceedings Vol. 8726:
Next-Generation Spectroscopic Technologies VI
Mark A. Druy; Richard A. Crocombe, Editor(s)