Broadband trace sensing using supercontinuum light sources

Supercontinuum light sources are attractive for spectroscopic applications in physics, chemistry and biology, owing to their unique combination of high spectral brightness and broadband wavelength coverage. We have developed a broadband multiple species trace gas detection scheme based on cavity enhanced absorption spectroscopy (CEAS) and a supercontinuum (SC) light source [1]. The method allows observation of spectra covering 100 nm or more all at once. We have applied this technique for quantitative measurement of NO
2
and NO
3
, species of importance in atmospheric chemistry. In the case of NO
3
, a sensitivity of three parts per trillion by volume was achieved for a measurement lasting less than 2s.