Pinto, D., Waclawek, J. P., Lindner, S., Moser, H., Ricchiuti, G., & Lendl, B. (2023). Highly sensitive and rugged gas optical detection via interferometric cavity-assisted photothermal spectroscopy. In L. E. Busse & Y. Soskind (Eds.), Photonic Instrumentation Engineering X. https://doi.org/10.1117/12.2648273
We report on the detection of nitric oxide using an Interferometric Cavity-Assisted Photothermal Spectroscopy (ICAPS) gas sensor in combination with a DFB-QCL emitting at 1900 cm-1 as excitation source. In ICAPS, a probe laser is coupled to a Fabry-Perot interferometer acting as an optical transducer of thermal effects. A wavelength modulation approach of the probe diode laser was employed, to actively lock its wavelength to the point of highest sensitivity and linearity of the interferometric fringe for a stable readout. A normalized noise equivalent absorption of 5·10-6 Wcm-1Hz-1/2 was achieved corresponding to 1.4 ppm of NO.
