Conception and reproducibility study of efficient evanescent Raman converters based a nanofiber immersed in a liquid

We demonstrate, build and optimize evanescent Raman converters at the sub-nanosecond regime based on a silica nanofiber immersed in ethanol. Two different standard silica fibers (SMF28, 460HP) are tested and compared. The converters are pumped at 532 nm and deliver pulses at 630 nm, which is the first Stokes order wavelength of ethanol. They present highly reproductible performances. A maximum output Stokes energy of 0.29 μJ is usually reached with an external conversion efficiency of 60%. Lowering the Raman threshold and pushing up the nanofiber breakdown allow a higher conversion operating range, that is the conception key of these converters.