High sensitivity gas sensing by Raman spectroscopy in photonic crystal fiber

We report the highly sensitive Raman detection of various gases (ambient nitrogen, oxygen, and carbon dioxide) and vapors (toluene, acetone, and 1,1,1-trichloroethane) using a hollow core photonic crystal fiber probe. With a sensitivity enhancement of around 3 orders of magnitude over direct detection, the minimum instrumentation-limited detectable concentrations for toluene, acetone, 1,1,1-trichloroethane vapors are 0.04%, 0.01%, 1.2%, respectively, with a 30 cm-long fiber probe. Moreover, we demonstrate its multiplexed sensing capability quantitatively using a vapor mixture. This combination of Raman spectroscopy and photonic crystal fiber provides a promising platform for gas sensing in environmental control applications.