Here, we present a protocol to perform sensitive, spatially resolved gas spectroscopy in the mid-infrared region, using degenerate four-wave mixing combined with upconversion detection.
Pedersen, R. L., Li, Z. Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing. J. Vis. Exp. (145), e59040, doi:10.3791/59040 (2019).