[Zurück]

J. Hayden, S. Hugger, F. Fuchs, B. Lendl:
"A quantum cascade laser-based Mach-Zehnder interferometer for chemical sensing employing molecular absorption and dispersion";
Applied Physics B - Lasers and Optics, 124 (2018), 2; S. 1 - 9.

We employ a novel spectroscopic setup based on an external cavity quantum cascade laser and a Mach-Zehnder interfer- ometer to simultaneously record spectra of absorption and dispersion of liquid samples in the mid-infrared. We describe the theory underlying the interferometric measurement and discuss its implications for the experiment. The capability of simultaneously recording a refractive index and absorption spectrum is demonstrated for a sample of acetone in cyclohex- ane. The recording of absorption spectra is experimentally investigated in more detail to illustrate the method´s capabili- ties as compared to direct absorption spectroscopy. We find that absorption signals are recorded with strongly suppressed background, but with smaller absolute sensitivity. A possibility of optimizing the setup´s performance by unbalancing the interferometer is presented.

http://dx.doi.org/10.1007/s00340-018-6899-8