1 Department of Photonics Engineering, Technical University of Denmark2 Optical Sensor Technology, Department of Photonics Engineering, Technical University of Denmark3 Risø National Laboratory for Sustainable Energy, Technical University of Denmark
We demonstrate a novel approach for high-resolution spectroscopy based on frequency upconversion and postfiltering by means of a scanning Fabryx2013;Perot interferometer. The system is based on sum-frequency mixing, shifting the spectral content from the mid-infrared to the near-visible region allowing for direct detection with a silicon-based CCD camera. This approach allows for low noise detection even without cooling of the detector. A setup is realized for the 3xA0;x3BC;m regime with a spectral resolution of 0.2xA0;nm using lithium niobate as the nonlinear material and mixing with a single-frequency 1064xA0;nm laser. We investigate water vapor emission lines from a butane burner and compare the measured results to model data. The presented method we suggest to be used for real-time monitoring of specific gas lines and reference signals.
Optics Letters, 2012, Vol 37, Issue 24, p. 5232-5234