Broadband cantilever-enhanced photoacoustic spectroscopy in the mid-IR using a supercontinuum

We demonstrate cantilever-enhanced photoacoustic spectroscopy in the mid-infrared using a supercontinuum source. The approach is broadband and allows for higher photoacoustic signal intensity and an enhanced signal-tonoise ratio as compared to systems employing conventional black body radiation sources. Using this technique, we perform spectroscopic measurements of the full ro-vibrational band structure of water vapor at 1900 nm and methane at 3300 nm with relative signal enhancement factors of 70 and 19, respectively, when compared to measurements that use the black body radiation source. Our results offer a novel perspective for photoacoustic detection opening the door to sensitive broadband analyzers in the mid-infrared spectral region. (C) 2018 Optical Society of America