GaAs/AlGaAs quantum cascade laser – a source for gas absorption spectroscopy

We report on an application of the recently developed electrically pumped GaAs/AlGaAs quantum cascade lasers in gas spectroscopy. Laser light with emission maximum at 10.009 μm is used to investigate the absorption in side bands of the vibrational spectrum of ethene at atmospheric pressure. Different mixtures of helium and ethene with known concentrations are flushed through an absorption cell. Laser radiation passing through the gas absorption cell is analyzed using a Fourier transform spectrometer. The laser spectrum is modulated by the ethene absorption. The experimentally obtained discrete spectrum is compared with the Hitran database, showing full agreement.