Fourier-Transform Mid-Infrared Spectroscopy Using Nonlinear Interferometers

Nonlinear interferometers allow mid infrared spectroscopy with silicon detectors. They are based on light sources that produce correlated photon pairs with spontaneous parametric down conversion (SPDC). There are multiple applications of this measurement technique, such as imaging [1], optical coherence tomography [2] or spectroscopy [3], [4]. Here, we employ a nonlinear interferometer to perform spectral analysis of a multi-gas sample, with a measurement concept that is analogue to classical Fourier-transform infrared (FTIR) spectrometers.