Pulsed quantum cascade laser based hypertemporal real-time headspace measurements

Abstract

Optical cavity enhancement is a highly desirable process to make sensitive direct-absorption spectroscopic measurements of unknown substances, such as explosive, illicit materials, or other species of interest. This paper reports advancements in the development of real-time cavity ringdown spectroscopy over a wide-bandwidth, with the aim to make heaadspace measurements of molecules at trace levels. We report results of two pulsed quantum cascade systems operating between (1200 to 1320) cm -1 and (1316 to 1613)cm -1 that measure the headspace of nitromethane, acetonitrile, acetone, and nitroglycerin, where the spectra are obtained in less than four seconds and contain at least 150,000 spectral wavelength datapoints.