Broadband Cavity Ringdown Spectroscopy for Sensitive and Rapid Molecular Detection
Michael J. Thorpe,
Kevin D. Moll,
R. Jason Jones,
Benjamin Safdi,
Jun Ye*
We demonstrate highly efficient cavity ringdown spectroscopy
in which a broad-bandwidth optical frequency comb is coherently
coupled to a high-finesse optical cavity that acts as the sample
chamber. 125,000 optical comb components, each coupled into
a specific longitudinal cavity mode, undergo ringdown decays
when the cavity input is shut off. Sensitive intracavity absorption
information is simultaneously available across 100 nanometers
in the visible and near-infrared spectral regions. Real-time,
quantitative measurements were made of the trace presence, the
transition strengths and linewidths, and the population redistributions
due to collisions and the temperature changes for molecules
such as C
2H
2, O
2, H
2O, and NH
3.
* To whom correspondence should be addressed. E-mail: ye{at}jila.colorado.edu
