We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-ampl...We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.展开更多
Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm i...Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm is still dominated by traditional fluoride(InF_(3))fibers.Although tellurite fibers,with their excellent chemical and thermal stability,have demonstrated significantly higher power scalability compared to other MIR fibers,their spectral broadening capabilities in the 4–5μm region remain largely unexplored.Here,we demonstrate a>10 W ultra-broadband flat SC spanning the 1.8–5.1μm spectral range in a fluorotellurite fiber using a cascaded soliton self-frequency shifting technique.The fluorotellurite fiber is precisely tapered to reconstruct dispersion and nonlinearity,which facilitates the evolution of the pre-stage Raman soliton into higherorder solitons,thereby enabling a new round of“rapid relay fission.”At a low pump power of 7.5 W,we also achieved a high-power(0.5 W)Raman soliton(60 fs)at 4.3μm.These results,for the first time,to our knowledge,demonstrate that tapered fluorotellurite fibers can be used for high-power femtosecond pulse generation beyond4μm and high-power SC generation beyond 5μm,establishing them as an exceptional nonlinear medium for the development of high-power MIR fiber lasers in the 4–5μm spectral region.展开更多
In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through ...In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through soliton fission in a silica fiber.By further cascading the 10 cm highly nonlinear fluorotellurite fiber,this Raman soliton undergoes successive high-order soliton fission and soliton self-frequency shift with a tunable range of 2.7–3.3μm.Such an ultra-short-length and ultra-large-core fiber significantly reduces the pulse width of the 3.3μm Raman soliton to 55 fs,doubling the peak power to 2.3 MW compared to previous studies.Furthermore,owing to the seed's high-repetition-frequency feature,the 3.3μm Raman soliton's power exceeds 2 W.These performance metrics represent the highest levels achieved for Raman solitons at wavelengths above 3μm,offering a simple and effective new approach for generating high-peak-power femtosecond pulses in the mid-infrared spectral region.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61675009 and 61325021)Key Program of Beijing Municipal Natural Science Foundation,China(Grant No.KZ201910005006).
文摘We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power.
基金National Natural Science Foundation of China(62005004,61675009)Natural Science Foundation of Beijing Municipality(4204091,KZ201910005006)China Postdoctoral Science Foundation(212423)。
文摘Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm is still dominated by traditional fluoride(InF_(3))fibers.Although tellurite fibers,with their excellent chemical and thermal stability,have demonstrated significantly higher power scalability compared to other MIR fibers,their spectral broadening capabilities in the 4–5μm region remain largely unexplored.Here,we demonstrate a>10 W ultra-broadband flat SC spanning the 1.8–5.1μm spectral range in a fluorotellurite fiber using a cascaded soliton self-frequency shifting technique.The fluorotellurite fiber is precisely tapered to reconstruct dispersion and nonlinearity,which facilitates the evolution of the pre-stage Raman soliton into higherorder solitons,thereby enabling a new round of“rapid relay fission.”At a low pump power of 7.5 W,we also achieved a high-power(0.5 W)Raman soliton(60 fs)at 4.3μm.These results,for the first time,to our knowledge,demonstrate that tapered fluorotellurite fibers can be used for high-power femtosecond pulse generation beyond4μm and high-power SC generation beyond 5μm,establishing them as an exceptional nonlinear medium for the development of high-power MIR fiber lasers in the 4–5μm spectral region.
基金supported by the National Natural Science Foundation of China(Grant Nos.62005004 and 61675009)the Natural Science Foundation of Beijing Municipality(Grant Nos.4204091 and KZ201910005006)the China Postdoctoral Science Foundation(Grant No.212423)。
文摘In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through soliton fission in a silica fiber.By further cascading the 10 cm highly nonlinear fluorotellurite fiber,this Raman soliton undergoes successive high-order soliton fission and soliton self-frequency shift with a tunable range of 2.7–3.3μm.Such an ultra-short-length and ultra-large-core fiber significantly reduces the pulse width of the 3.3μm Raman soliton to 55 fs,doubling the peak power to 2.3 MW compared to previous studies.Furthermore,owing to the seed's high-repetition-frequency feature,the 3.3μm Raman soliton's power exceeds 2 W.These performance metrics represent the highest levels achieved for Raman solitons at wavelengths above 3μm,offering a simple and effective new approach for generating high-peak-power femtosecond pulses in the mid-infrared spectral region.
