When a high energy nanosecond(ns)laser induces breakdown in the air,the plasma density generated in the rarefied atmosphere is much smaller than that at normal pressure.It is associated with a relatively lower absorpt...When a high energy nanosecond(ns)laser induces breakdown in the air,the plasma density generated in the rarefied atmosphere is much smaller than that at normal pressure.It is associated with a relatively lower absorption coefficient and reduces energy loss of the laser beam at low pressure.In this paper,the general transmission characterizations of a Joule level 10 ns 1064 nm focused laser beam are investigated both theoretically and experimentally under different pressures.The evolution of the electron density(n_(e)),the changes in electron temperature(T_(e))and the variation of laser intensity(I)are employed for numerical analyses in the simulation model.For experiments,four optical image transfer systems with focal length(f)of 200 mm are placed in a chamber and employed to focus the laser beam and produce plasmas at the focus.The results suggest that the transmittance increases obviously with the decreasing pressure and the plasma channels on the transmission path can be observed by the self-illumination.The simulation results agree well with the experimental data.The numerical model presents that the maximum n_e at the focus can reach 10^(19)cm^(-3),which is far below the critical density(n_(c)).As a result,the laser beam is not completely shielded by the plasmas.展开更多
The influence of pumping laser pulse on the property of quasi-continuous-wave(QCW)diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally.Under remaining a fixed duty cycle,the average output p...The influence of pumping laser pulse on the property of quasi-continuous-wave(QCW)diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally.Under remaining a fixed duty cycle,the average output power increases,and the corresponding thermal focal length shorten with the increase of the pump pulse duration,which attributes to the decrease of the ratio of pulse buildup time to the pulse duration.At a pump power of 146 W,the laser output power changes from 65.1 W to 81.2 W when the pulse duration is adjusted from 150μs to 1000μs,confirming a significant enhancement of 24.7%.A laser rate equation model incorporating the amplified spontaneous emission is also utilized and numerically solved,and the simulated results agree well with the experimental data.展开更多
A single frequency photonic bandgap fiber amplifier at 11 78nm is iuvestigated experimentally and numerically.With a pump power of 81 W, a single frequency 1178nm fiber laser of 10.3 W is obtained with a 3 W seed lase...A single frequency photonic bandgap fiber amplifier at 11 78nm is iuvestigated experimentally and numerically.With a pump power of 81 W, a single frequency 1178nm fiber laser of 10.3 W is obtained with a 3 W seed laser and a 20m gain fiber. Numerical simulation is conducted with a rate equation model taking amplified spontaneous emission and stimulated Brillouin scattering （SBS） into consideration. Temperature distribution along the fiber is applied for SBS suppression, more than 50 W single frequeney fiber laser at 1178 nm is predicted theoreticall.v with a 5 W seed laser and a 40m long gain fiber with five temperature steps.展开更多
The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror （SESAM）. Two narrow-band fiber Bragg gratings cent...The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror （SESAM）. Two narrow-band fiber Bragg gratings centered at 1029.9nm and 1032nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9nm and 1032nm. The laser delivers different pulse widths of 7.5ps for 1030nm and 20ps for 1032nm. The maximum output power for both could reach -6.5mW at single pulse operation. The output wavelength couM be tuned to about 0.gnm intervals ranging from 1030.2nm to 1031.1 nm and from 1032.15nm to 1033.7nm with the temperature change of the fiber Bragg grating, respectively.展开更多
A high-efficiency and high-power vertical-cavity surface-emitting laser(VCSEL) side-pumped rod Nd:YAG laser with temperature adaptability are demonstrated. The VCSEL side-pumped laser module is designed and optimized....A high-efficiency and high-power vertical-cavity surface-emitting laser(VCSEL) side-pumped rod Nd:YAG laser with temperature adaptability are demonstrated. The VCSEL side-pumped laser module is designed and optimized. Five VCSEL arrays are symmetrically located around the laser rod and a large size diffused reflection chamber is designed to ensure a uniform pump distribution. Furthermore, the absorbed pump power distribution of the rod is simulated to verify the uniformity of the pump absorption. Finally, a proof-of-principle experiment is performed in short linear cavity laser with single laser module. A continuous-wave output power of 658 W at 1064 nm is obtained, the corresponding optical-to-optical efficiency is 52.6%, and the power variations are ±0.7% over 400 s and ±3.1% over the temperature range from 16 ℃ to 26 ℃. To the best of our knowledge, this is the highest output power and the highest optical-to-optical efficiency ever reported for VCSEL pumped solid-state lasers. By inserting a telescopic module into the cavity and optimizing the TEM_(00) mode volume, the average beam quality is measured to be M~2= 1.34 under an output power of 102 W. The experimental results reveal that such a high power rod laser module with temperature stability is appropriate for field applications.展开更多
Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single...Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single-frequency Nd:YAG oscillator is obtained.The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported.The result proves that this method does help for energy enhancement.It has attractive potential for high energy single frequency oscillator design,especially on condition of intensive side pumped or long cavity laser,where strong competitors exist and are hard to be suppressed.展开更多
The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration va...The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.展开更多
We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm.Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser,which is suppressed by pumping with a fiber laser...We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm.Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser,which is suppressed by pumping with a fiber laser at 1018 nm.At least four times improvement in output peak power is demonstrated in a single laser setup with 1018-nm fiber laser pumping instead of 976-nm laser diode pumping.This is,to the best of our knowledge,the first demonstration of a tandem-pumped Q-switched fiber laser.展开更多
Photoreflectance(PR)spectroscopy is a powerful and non-destructive experimental technique to explore interband transitions of semiconductors.In most PR systems,the photon energy of the pumping beam is usually chosen t...Photoreflectance(PR)spectroscopy is a powerful and non-destructive experimental technique to explore interband transitions of semiconductors.In most PR systems,the photon energy of the pumping beam is usually chosen to be higher than the bandgap energy of the sample.To the best of our knowledge,the highest energy of pumping laser in reported PR systems is 5.08 eV(244 nm),not yet in the vacuum ultraviolet(VUV)region.In this work,we report the design and construction of a PR system pumped by VUV laser of 7.0 eV(177.3 nm).At the same time,dual-modulated technique is applied and a dual channel lock-in-amplifier is integrated into the system for efficient PR measurement.The system’s performance is verified by the PR spectroscopy measurement of well-studied semiconductors,which testifies its ability to probe critical-point energies of the electronic band in semiconductors from ultraviolet to near-infrared spectral region.展开更多
A high power continuous-wave single-frequency green fiber laser by second-harmonic generation of a Yb-doped fiber amplifier（YDFA）is developed.A linearly polarized single-mode fiber amplifier produces a 60 W infrared...A high power continuous-wave single-frequency green fiber laser by second-harmonic generation of a Yb-doped fiber amplifier（YDFA）is developed.A linearly polarized single-mode fiber amplifier produces a 60 W infrared laser at 1064 nm with a 103 W incident diode pump laser at 976 nm,corresponding to an optical conversion efficiency of 58%.An external bow-tie enhancement cavity incorporating a noncritically phase-matched lithium triborate crystal is employed for second-harmonic generation.A 33.2 W laser at 532 nm is obtained with a 45 W incident 1064 nm fundamental laser,corresponding to a conversion efficiency of 74%.展开更多
We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear cr...We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear crystal KBe2BO3F2(KBBF)is used to generate deep ultraviolet and vacuum ultraviolet laser radiation,which complements traditional incoherent light sources such as gas discharge lamps and synchrotron radiation,and has greatly improved resolution with respect to energy,momentum,and spin of photoemission spectroscopy.Many new functions have been developed with the advantages of high photon energy,narrow linewidth,high photon flux density,and so on.These have led to the observation of various new phenomena and the amassment of new data in the fields of high temperature superconductivity,topological electronics,Fermi semi-metals,and so forth.These laser systems have revived the field of photoemission spectroscopy and provided a new platform in this frontier research field.展开更多
Ultrafast Raman fiber laser has been proved to be an effective method to obtain ultrafast optical pulses at special wavelength.Yet,compared with conventional rareearth doped counterparts,it is challenging for Raman fi...Ultrafast Raman fiber laser has been proved to be an effective method to obtain ultrafast optical pulses at special wavelength.Yet,compared with conventional rareearth doped counterparts,it is challenging for Raman fiber lasers to generate pulses with high pulse energy and short pulse duration.Here,we review three categories of ultrafast Raman fiber laser technologies and give detailed discussions on the advantages and challenges of each.In regards to mode-locking,different saturable-absorbers-based fiber lasers are compared and their common problem resulting from long cavity length are discussed.In terms of synchronously-pumping,several approaches to match the repetition rate of pulsed pump with the length of Raman fiber cavity are discussed,while the technical complexity of each method is analyzed.Moreover,the recently developed technology termed as nonlinear optical gain modulation(NOGM)is introduced,which turns out to be a simple and quality solution to generate highenergy femtosecond pulses with wavelength agility.Compared with the others,NOGM gathers various advantages including simple structure,long-term stability,high pulse energy and short pulse duration,which may effectively promote application expansion of ultrafast Raman fiber laser in the near future.展开更多
We report the first demonstration on three types of 1.3 μm spectral region in a Q-switched Nd:YAG laser. In order to dissipate the heat deposition effectively to obtain good beam quality, the Nd:YAG rod crystal with ...We report the first demonstration on three types of 1.3 μm spectral region in a Q-switched Nd:YAG laser. In order to dissipate the heat deposition effectively to obtain good beam quality, the Nd:YAG rod crystal with 1° cut-angle on end faces is side-pumped by the quasi-continuous-wave pulsed laser diode. A Suprasil etalon is well designed as the intracavity mode-selector to obtain wavelength-tunable single line or power-ratio-controllable dual line operation at1319 nm and 1338 nm. With the pump pulse width of 200 μs and pump power of 410 W, the acousto-optic Q-switched laser delivered a pulse width of 117 ns at 400 Hz repetition rate, and the M2factor was measured to be about 1.87. 1319 nm together with 1338 nm single-wavelength laser achieved an average output power of 47.6 W and 39.9 W with a linewidth of 0.48 nm and 0.32 nm, and a tunable range of 111.2 pm and108.6 pm, respectively. Among dual-wavelength oscillation, both lines can be tuned at almost equal intensity level with 45.7 W total output power, which is input into an LBO crystal to generate red light of 11.4 W for 659 nm,6.7 W for 664 nm, and 7.5 W for 669 nm. The 1.3 μm wavelength-selectable operation realized by using the same laser configuration may enhance the application in the fields of tunable lasers and THz frequency generation.展开更多
In this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization ro- tation technique operating under dissipative soliton （DS） or dissipative soliton resonance （DSR） cond...In this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization ro- tation technique operating under dissipative soliton （DS） or dissipative soliton resonance （DSR） conditions is proposed. Furthermore, using a combination of a bandpass filter and a Loyt filter, tunable single-wavelength or dual-wavelength operation under two different conditions is realized, respectively. The tunable single- wavelength DS laser has a 5 nm tuning range from 1029 to 1034 nm with a pulse width of 110 ps. The tunable single-wavelength DSR operation laser has a range of 4 nm. In-depth research on the mechanism of the con- version between DS and DSR is carried out. Particularly, under dual-wavelength DSR operation, the obtained step-like pulses consist of two rectangular pulses with different energies. This work could help give a deeper insight into normal dispersion pulses.展开更多
基金Project supported by the Science and Technology Innovation Foundation of the Chinese Academy of Sciences(Grant No.CXJJ-20S020)。
文摘When a high energy nanosecond(ns)laser induces breakdown in the air,the plasma density generated in the rarefied atmosphere is much smaller than that at normal pressure.It is associated with a relatively lower absorption coefficient and reduces energy loss of the laser beam at low pressure.In this paper,the general transmission characterizations of a Joule level 10 ns 1064 nm focused laser beam are investigated both theoretically and experimentally under different pressures.The evolution of the electron density(n_(e)),the changes in electron temperature(T_(e))and the variation of laser intensity(I)are employed for numerical analyses in the simulation model.For experiments,four optical image transfer systems with focal length(f)of 200 mm are placed in a chamber and employed to focus the laser beam and produce plasmas at the focus.The results suggest that the transmittance increases obviously with the decreasing pressure and the plasma channels on the transmission path can be observed by the self-illumination.The simulation results agree well with the experimental data.The numerical model presents that the maximum n_e at the focus can reach 10^(19)cm^(-3),which is far below the critical density(n_(c)).As a result,the laser beam is not completely shielded by the plasmas.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402103)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.GJJSTD20180004)the Fund of Technical Institute of Physics and Chemistry,Chinese Academy of Sciences(Grant No.Y8A9021H11)。
文摘The influence of pumping laser pulse on the property of quasi-continuous-wave(QCW)diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally.Under remaining a fixed duty cycle,the average output power increases,and the corresponding thermal focal length shorten with the increase of the pump pulse duration,which attributes to the decrease of the ratio of pulse buildup time to the pulse duration.At a pump power of 146 W,the laser output power changes from 65.1 W to 81.2 W when the pulse duration is adjusted from 150μs to 1000μs,confirming a significant enhancement of 24.7%.A laser rate equation model incorporating the amplified spontaneous emission is also utilized and numerically solved,and the simulated results agree well with the experimental data.
文摘A single frequency photonic bandgap fiber amplifier at 11 78nm is iuvestigated experimentally and numerically.With a pump power of 81 W, a single frequency 1178nm fiber laser of 10.3 W is obtained with a 3 W seed laser and a 20m gain fiber. Numerical simulation is conducted with a rate equation model taking amplified spontaneous emission and stimulated Brillouin scattering （SBS） into consideration. Temperature distribution along the fiber is applied for SBS suppression, more than 50 W single frequeney fiber laser at 1178 nm is predicted theoreticall.v with a 5 W seed laser and a 40m long gain fiber with five temperature steps.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2014AA041901NSAF Foundation of the National Natural Science Foundation of China under Grant No U1330134+1 种基金the Opening Project of Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques under Grant No 2012ADL02the National Natural Science Foundation of China under Grant Nos 61308024 and 11174305
文摘The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror （SESAM）. Two narrow-band fiber Bragg gratings centered at 1029.9nm and 1032nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9nm and 1032nm. The laser delivers different pulse widths of 7.5ps for 1030nm and 20ps for 1032nm. The maximum output power for both could reach -6.5mW at single pulse operation. The output wavelength couM be tuned to about 0.gnm intervals ranging from 1030.2nm to 1031.1 nm and from 1032.15nm to 1033.7nm with the temperature change of the fiber Bragg grating, respectively.
文摘A high-efficiency and high-power vertical-cavity surface-emitting laser(VCSEL) side-pumped rod Nd:YAG laser with temperature adaptability are demonstrated. The VCSEL side-pumped laser module is designed and optimized. Five VCSEL arrays are symmetrically located around the laser rod and a large size diffused reflection chamber is designed to ensure a uniform pump distribution. Furthermore, the absorbed pump power distribution of the rod is simulated to verify the uniformity of the pump absorption. Finally, a proof-of-principle experiment is performed in short linear cavity laser with single laser module. A continuous-wave output power of 658 W at 1064 nm is obtained, the corresponding optical-to-optical efficiency is 52.6%, and the power variations are ±0.7% over 400 s and ±3.1% over the temperature range from 16 ℃ to 26 ℃. To the best of our knowledge, this is the highest output power and the highest optical-to-optical efficiency ever reported for VCSEL pumped solid-state lasers. By inserting a telescopic module into the cavity and optimizing the TEM_(00) mode volume, the average beam quality is measured to be M~2= 1.34 under an output power of 102 W. The experimental results reveal that such a high power rod laser module with temperature stability is appropriate for field applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.11504389)the Funds of Key Lab of Function Crystal and Laser Technology,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences
文摘Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single-frequency Nd:YAG oscillator is obtained.The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported.The result proves that this method does help for energy enhancement.It has attractive potential for high energy single frequency oscillator design,especially on condition of intensive side pumped or long cavity laser,where strong competitors exist and are hard to be suppressed.
基金Supported by the National High-Technology Research and Development Program of China under Grant No 2014AA041901the NSAF Foundation of National Natural Science Foundation of China under Grant No U1330134+1 种基金the Opening Project of Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques under Grant No 2012ADL02the National Natural Science Foundation of China under Grant No 61308024
文摘The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.
文摘We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm.Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser,which is suppressed by pumping with a fiber laser at 1018 nm.At least four times improvement in output peak power is demonstrated in a single laser setup with 1018-nm fiber laser pumping instead of 976-nm laser diode pumping.This is,to the best of our knowledge,the first demonstration of a tandem-pumped Q-switched fiber laser.
基金Project supported by the National Development Project for Major Scientific Research Facility of China(Grant No.ZDYZ2012-2)the National Natural Science Foundation of China(Grant No.11874350)CAS Key Research Program of Frontier Sciences(Grant Nos.ZDBS-LY-SLH004 and XDPB22)。
文摘Photoreflectance(PR)spectroscopy is a powerful and non-destructive experimental technique to explore interband transitions of semiconductors.In most PR systems,the photon energy of the pumping beam is usually chosen to be higher than the bandgap energy of the sample.To the best of our knowledge,the highest energy of pumping laser in reported PR systems is 5.08 eV(244 nm),not yet in the vacuum ultraviolet(VUV)region.In this work,we report the design and construction of a PR system pumped by VUV laser of 7.0 eV(177.3 nm).At the same time,dual-modulated technique is applied and a dual channel lock-in-amplifier is integrated into the system for efficient PR measurement.The system’s performance is verified by the PR spectroscopy measurement of well-studied semiconductors,which testifies its ability to probe critical-point energies of the electronic band in semiconductors from ultraviolet to near-infrared spectral region.
文摘A high power continuous-wave single-frequency green fiber laser by second-harmonic generation of a Yb-doped fiber amplifier（YDFA）is developed.A linearly polarized single-mode fiber amplifier produces a 60 W infrared laser at 1064 nm with a 103 W incident diode pump laser at 976 nm,corresponding to an optical conversion efficiency of 58%.An external bow-tie enhancement cavity incorporating a noncritically phase-matched lithium triborate crystal is employed for second-harmonic generation.A 33.2 W laser at 532 nm is obtained with a 45 W incident 1064 nm fundamental laser,corresponding to a conversion efficiency of 74%.
基金Project supported by the National Development Project for Major Scientific Research Facility(No.ZDYZ2012-2)the National Instrumentation Program(No.2012YQ120048)
文摘We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear crystal KBe2BO3F2(KBBF)is used to generate deep ultraviolet and vacuum ultraviolet laser radiation,which complements traditional incoherent light sources such as gas discharge lamps and synchrotron radiation,and has greatly improved resolution with respect to energy,momentum,and spin of photoemission spectroscopy.Many new functions have been developed with the advantages of high photon energy,narrow linewidth,high photon flux density,and so on.These have led to the observation of various new phenomena and the amassment of new data in the fields of high temperature superconductivity,topological electronics,Fermi semi-metals,and so forth.These laser systems have revived the field of photoemission spectroscopy and provided a new platform in this frontier research field.
基金supported by Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2022247)National Natural Science Foundation of China(No.62075226,62175244)+1 种基金Natural Science Foundation of Shanghai(No.21ZR1472200)Youth Innovation Promotion Association,Chinese Academy of Sciences,2022247,Jiaqi Zhou,National Natural Science Foundation of China,62075226,Yan Feng,62175244,Jiaqi Zhou,Natural Science Foundation of Shanghai,21ZR1472200,Jiaqi Zhou.
文摘Ultrafast Raman fiber laser has been proved to be an effective method to obtain ultrafast optical pulses at special wavelength.Yet,compared with conventional rareearth doped counterparts,it is challenging for Raman fiber lasers to generate pulses with high pulse energy and short pulse duration.Here,we review three categories of ultrafast Raman fiber laser technologies and give detailed discussions on the advantages and challenges of each.In regards to mode-locking,different saturable-absorbers-based fiber lasers are compared and their common problem resulting from long cavity length are discussed.In terms of synchronously-pumping,several approaches to match the repetition rate of pulsed pump with the length of Raman fiber cavity are discussed,while the technical complexity of each method is analyzed.Moreover,the recently developed technology termed as nonlinear optical gain modulation(NOGM)is introduced,which turns out to be a simple and quality solution to generate highenergy femtosecond pulses with wavelength agility.Compared with the others,NOGM gathers various advantages including simple structure,long-term stability,high pulse energy and short pulse duration,which may effectively promote application expansion of ultrafast Raman fiber laser in the near future.
基金National Natural Science Foundation of China(62005295)National Key Research and Development Program of China(2016YFB0402103).
文摘We report the first demonstration on three types of 1.3 μm spectral region in a Q-switched Nd:YAG laser. In order to dissipate the heat deposition effectively to obtain good beam quality, the Nd:YAG rod crystal with 1° cut-angle on end faces is side-pumped by the quasi-continuous-wave pulsed laser diode. A Suprasil etalon is well designed as the intracavity mode-selector to obtain wavelength-tunable single line or power-ratio-controllable dual line operation at1319 nm and 1338 nm. With the pump pulse width of 200 μs and pump power of 410 W, the acousto-optic Q-switched laser delivered a pulse width of 117 ns at 400 Hz repetition rate, and the M2factor was measured to be about 1.87. 1319 nm together with 1338 nm single-wavelength laser achieved an average output power of 47.6 W and 39.9 W with a linewidth of 0.48 nm and 0.32 nm, and a tunable range of 111.2 pm and108.6 pm, respectively. Among dual-wavelength oscillation, both lines can be tuned at almost equal intensity level with 45.7 W total output power, which is input into an LBO crystal to generate red light of 11.4 W for 659 nm,6.7 W for 664 nm, and 7.5 W for 669 nm. The 1.3 μm wavelength-selectable operation realized by using the same laser configuration may enhance the application in the fields of tunable lasers and THz frequency generation.
基金supported in part by the National High Technology Research and Development Program of China (No.2014AA041901)the NSAF Foundation of National Natural Science Foundation of China(No.U1330134)+2 种基金the project of Shandong Province Higher Educational Scienceand Technology Program(No.J13LJ06)the National Natural Science Foundation of China(No.61308024)the National Natural Science Fund(No.11174305)
文摘In this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization ro- tation technique operating under dissipative soliton （DS） or dissipative soliton resonance （DSR） conditions is proposed. Furthermore, using a combination of a bandpass filter and a Loyt filter, tunable single-wavelength or dual-wavelength operation under two different conditions is realized, respectively. The tunable single- wavelength DS laser has a 5 nm tuning range from 1029 to 1034 nm with a pulse width of 110 ps. The tunable single-wavelength DSR operation laser has a range of 4 nm. In-depth research on the mechanism of the con- version between DS and DSR is carried out. Particularly, under dual-wavelength DSR operation, the obtained step-like pulses consist of two rectangular pulses with different energies. This work could help give a deeper insight into normal dispersion pulses.
