Cavity ring-down spectroscopy in uniform supersonic flows
Shameemah and Nicolas at the new UF-CRDS machine

The Uniform-Flow Cavity Ring-Down Spectroscopy instrument is the first in the world to combine cw-CRDS with a Laval flow. With it we have recently demonstrated Simultaneous Kinetics and Ring-down (SKaR) in a Laval Flow, allowing a complete low temperature kinetics measurement to be obtained in 2 hours. The current apparatus can be configured either with an external cavity diode laser (ECDL), tunable between 1280-1380 nm or a distributed feedback (DFB) diode laser, tunable between 1411-1419 nm. The high sensitivity of the cw-CRDS technique itself and the tunability of the detection wavelength in the near IR range extends the ability of detection of electronic and rovibrational transitions of reactants and intermediates within low temperature Laval flow (15 to 70 K). Our main interest lies in studying reaction kinetics and spectroscopy of such species produced in uniform Laval flow, similar to what has been demonstrated by the CRESU technique using LIF.

N. Suas-David, S. Thawoos and A. G. Suits, “A Uniform Flow – Cavity Ring-Down Spectrometer (UF-CRDS):  A new setup for spectroscopy and kinetics at low temperature,” J Chem. Phys. (2019) 151, 244202. https://doi.org/10.1063/1.5125574 (Featured Article)