Raman scattering provides a convenient mechanism to generate or amplify light at wavelengths where gain is not otherwise available.When combined with recent advancements in high-power fiber lasers that operate at wave...Raman scattering provides a convenient mechanism to generate or amplify light at wavelengths where gain is not otherwise available.When combined with recent advancements in high-power fiber lasers that operate at wavelengths~2μm,great opportunities exist for Raman systems that extend operation further into the mid-infrared regime for applications such as gas sensing,spectroscopy,and biomedical analyses.Here,a thulium-doped fiber laser is used to demonstrate Raman emission and amplification from a highly nonlinear silicon core fiber(SCF)platform at wavelengths beyond 2μm.The SCF has been tapered to obtain a micrometer-sized core diameter(~1.6μm)over a length of 6 cm,with losses as low as 0.2 dB cm^(−1).A maximum on-off peak gain of 30.4 dB was obtained using 10 W of peak pump power at 1.99μm,with simulations indicating that the gain could be increased to up to~50 dB by extending the SCF length.Simulations also show that by exploiting the large Raman gain and extended mid-infrared transparency of the SCF,cascaded Raman processes could yield tunable systems with practical output powers across the 2–5μm range.展开更多
基金support from the following funding bodies:A.C.P.—Engineering and Physical Sciences Research Council(EPSRC,EP/P000940/1)Q.F.—EPSRC(EP/P027644/1)+2 种基金J.B.and T.W.H.—J.E.Sirrine FoundationL.S.—National Natural Science Foundation of China(62175080)M.H.—Chinese Scholarships Council.
文摘Raman scattering provides a convenient mechanism to generate or amplify light at wavelengths where gain is not otherwise available.When combined with recent advancements in high-power fiber lasers that operate at wavelengths~2μm,great opportunities exist for Raman systems that extend operation further into the mid-infrared regime for applications such as gas sensing,spectroscopy,and biomedical analyses.Here,a thulium-doped fiber laser is used to demonstrate Raman emission and amplification from a highly nonlinear silicon core fiber(SCF)platform at wavelengths beyond 2μm.The SCF has been tapered to obtain a micrometer-sized core diameter(~1.6μm)over a length of 6 cm,with losses as low as 0.2 dB cm^(−1).A maximum on-off peak gain of 30.4 dB was obtained using 10 W of peak pump power at 1.99μm,with simulations indicating that the gain could be increased to up to~50 dB by extending the SCF length.Simulations also show that by exploiting the large Raman gain and extended mid-infrared transparency of the SCF,cascaded Raman processes could yield tunable systems with practical output powers across the 2–5μm range.
