We present a new detection scheme for carbon dioxide(CO2) based on a custom-made room temperature distributed
feedback (DFB) diode laser at 2.7 μm, currently representing the laser with the highest emission wavelength of its kind.
The detector's especially compact and simple set-up is based on photoacoustic spectroscopy (PAS). This method makes
use of the transformation of absorbed modulated radiation into a sound wave. The sensor enables a very high detection
sensitivity for CO2 in the ppb range. Furthermore, the carefully selected spectral region as well as the narrow bandwidth
and wide tunability of the single-mode laser ensure an excellent selectivity. Even measurements of different CO2
isotopes can be easily performed. This could enable future applications of this spectroscopic sensor in medical
diagnostics (e.g. 13C-breath tests).