@article{12378,
  author = {Qizhong Liang and Ya-Chu Chan and Bryan Changala and David Nesbitt and Jun Ye and Jutta Toscano},
  title = {Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics},
  abstract = {Breath analysis enables rapid, non-invasive diagnostics, as well as long-term monitoring, of human health through the identification and quantification of exhaled biomarkers. Here, for the first time, we demonstrate the remarkable capabilities of mid-infrared (mid-IR) cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) applied to breath analysis. We simultaneously detect and monitor as a function of time four breath biomarkers - CH3OH, CH4, H2O and HDO - as well as illustrating the feasibility of detecting at least six more (H2CO, C2H6, OCS, C2H4, CS2 and NH3) without modifications to the experimental apparatus. We achieve ultra-high detection sensitivity at the parts-per-trillion level. This is made possible by the combination of the broadband spectral coverage of a frequency comb, the high spectral resolution afforded by the individual comb teeth, and the sensitivity enhancement resulting from a high-finesse cavity. Exploiting recent advances in frequency comb, optical coating, and photodetector technologies, we can access a large variety of biomarkers with strong carbon-hydrogen bond spectral signatures in the mid-IR.},
  year = {2021},
  journal = {Proc. Natl. Acad. Sci. },
  volume = {118},
  pages = {e2105063118},
  month = {2021-10},
  url = {https://www.pnas.org/content/118/40/e2105063118},
  doi = {10.1073/pnas.2105063118},
}