We report on a novel means which lifts the restriction of the limited optical bandwidth of photonic bandgap hollow-core photonic crystal fiber on generating high order stimulated Raman scattering in gaseous media. This is based on H-2-filled tapered HC-PCF in which the taper slope is matched with the effective length of Raman process. Raman orders outside the input-bandwidth of the HC-PCF are observed with more than 80% quantum-conversion using a compact, low-power 1064 nm microchip laser. The technique opens prospects for efficient sources in spectral regions that are poorly covered by currently existing lasers such as mid-IR.
Beaudou, B., Couny, F., Wang, Y. Y., Light, P. S., Wheeler, N. V., Gerome, F., & Benabid, F. (2010). Matched cascade of bandgap-shift and frequency-conversion using stimulated Raman scattering in a tapered hollow-core photonic crystal fibre. Optics Express, 18(12), 12381-12390. https://doi.org/10.1364/OE.18.012381