Sensitivity enhancement in high resolution stimulated Raman spectroscopy of gases with hollow-core photonic crystal fibers

We show the first experimental evidence of the sensitivity enhancement that can be achieved in high resolution stimulated Raman spectroscopy of gases using hollow-core photonic crystal fibers (HCPCFs). Using low power cw lasers and a HCPCF containing the gas, we have observed more than four orders of magnitude enhancement of sensitivity when compared with the cw single focus regime, and a similar sensitivity to that achieved in the more sensitive quasi-cw setups with multipass cells.