An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively intro...An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability(TMI) suppression. The stimulated Brillouin scattering(SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ～0.025, 0.17 and ～0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3times. The beam quality(M～2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the influence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering(SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multidetrimental effects(SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth fiber amplifiers.展开更多
We present a lamp-pumped Nd： phosphate glass laser amplifier delivering up to 1 J of pulse energy at 1053 nm with a repetition rate of 1 Hz and an injected pulse energy of 2.5 mJ. The amplifier system employs a beams...We present a lamp-pumped Nd： phosphate glass laser amplifier delivering up to 1 J of pulse energy at 1053 nm with a repetition rate of 1 Hz and an injected pulse energy of 2.5 mJ. The amplifier system employs a beamshaping module and a four-pass, lamp-pumped amplifier. The thermally induced wavefront distortion is mitigated and a uniform gain distribution is obtained by a four-lamp-pmnped laser head in the amplifier. Thus, an excellent beam quality is obtained.展开更多
Compared with traditional uniform fibers, tapered fiber has numerous unique advantages, such as larger mode area,higher pump absorption, suppression to nonlinear effects, and maintaining good beam quality. In this man...Compared with traditional uniform fibers, tapered fiber has numerous unique advantages, such as larger mode area,higher pump absorption, suppression to nonlinear effects, and maintaining good beam quality. In this manuscript, we have constructed an all-fiberized fiber amplifier which is based on a piece of ytterbium-doped tapered double-clad fiber(T-DCF). The fiber amplifier is operated under continuous wave(CW) regime at 1080 nm wavelength. The M2 factor of the amplifier at 1.39 k W output power is ～1.8. The maximum output power of the system reached 1.47 k W, which, to the best of our knowledge, is the highest output power of long tapered fiber based fiber laser system. Our result successfully verifies the potential of power scalability and all-fiberized capability of long tapered fiber, and the performance of our system can be further enhanced by fiber design optimization.展开更多
A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durati...A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durations of 3–5 ns and beam diameter 60 mm, employs a sequence of successive rod amplifiers to achieve 100-J-level energy at 1053 nm at3 ns. The frequency conversion can provide energy of 50-J level at 351 nm. In addition to the high stability of the energy output, the most valuable of the laser system is the high spatiotemporal beam quality of the output, which contains the uniform square pulse waveform, the uniform flat-top spatial fluence distribution and the uniform flat-top wavefront.展开更多
In this paper we review the design and development of a 100 J, 10 Hz nanosecond pulsed laser, codenamed DiPOLE100 X,being built at the Central Laser Facility(CLF). This 1 kW average power diode-pumped solid-state lase...In this paper we review the design and development of a 100 J, 10 Hz nanosecond pulsed laser, codenamed DiPOLE100 X,being built at the Central Laser Facility(CLF). This 1 kW average power diode-pumped solid-state laser(DPSSL) is based on a master oscillator power amplifier(MOPA) design, which includes two cryogenic gas cooled amplifier stages based on DiPOLE multi-slab ceramic Yb:YAG amplifier technology developed at the CLF. The laser will produce pulses between 2 and 15 ns in duration with precise, arbitrarily selectable shapes, at pulse repetition rates up to 10 Hz, allowing real-time shape optimization for compression experiments. Once completed, the laser will be delivered to the European X-ray Free Electron Laser(XFEL) facility in Germany as a UK-funded contribution in kind, where it will be used to study extreme states of matter at the High Energy Density(HED) instrument.展开更多
Optical damages, which severely degrade the output energy performance of Nd:glass regenerative amplifiers, are discussed in detail in this paper. By a series of experiments, it has been confirmed that these damages re...Optical damages, which severely degrade the output energy performance of Nd:glass regenerative amplifiers, are discussed in detail in this paper. By a series of experiments, it has been confirmed that these damages result from laser-induced contamination. Based on this work, several improvements are made to boost output energy performance of the regenerative amplifier. The output energy of the regenerative amplifier after improvements declines 4% after 1000 h of operation, much less than it used to, 60% after 560 h of operation.展开更多
近年来随着光电技术应用需求的增长,诸如平面激光诱导荧光技术、激光探测和激光加工等越来越多的领域展现出对高重频大能量的脉冲激光的需求。然而受激光器平均功率的限制,传统的连续脉冲模式的脉冲激光器难以实现高重频和大能量的兼顾...近年来随着光电技术应用需求的增长,诸如平面激光诱导荧光技术、激光探测和激光加工等越来越多的领域展现出对高重频大能量的脉冲激光的需求。然而受激光器平均功率的限制,传统的连续脉冲模式的脉冲激光器难以实现高重频和大能量的兼顾输出。文中研究了一种LD泵浦Nd:YAG1.06μm脉冲串激光器及其放大系统。采用长脉冲泵浦、腔内调制和MOPA放大技术,实现了一段时间内激光器的高重频和大能量的兼顾输出。在调Q重频分别为10、50、100 k Hz时,脉冲串能量分别达到170.4、211.8、220.3 mJ,每串内分别包含2个、12个、25个脉冲,单脉冲能量分别为85.2、17.7、8.8 mJ。展开更多
We report on the energetic and beam quality performance of the second to the last main amplifier section HEPA I of the PENELOPE laser project. A polarization coupled double-12-pass scheme to verify the full amplificat...We report on the energetic and beam quality performance of the second to the last main amplifier section HEPA I of the PENELOPE laser project. A polarization coupled double-12-pass scheme to verify the full amplification capacity of the last two amplifiers HEPA I and II was used. The small signal gain for a narrow-band continuous wave laser was 900 and 527 for a broadband nanosecond pulse, demonstrating 12.6 J of output pulse energy. Those pulses, being spectrally wide enough to support equivalent 150 fs long ultrashort pulses, are shown with an excellent spatial beam quality. A first active correction of the wavefront using a deformable mirror resulted in a Strehl ratio of 76% in the single-12-pass configuration for HEPA I.展开更多
The development,the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed.Currently,the POLARIS system delivers 4 J energy,144 fs long laser pulses with an...The development,the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed.Currently,the POLARIS system delivers 4 J energy,144 fs long laser pulses with an ultra-high temporal contrast of 5 × 1012 for the ASE,which is achieved using a so-called double chirped-pulse amplification scheme and cross-polarized wave generation pulse cleaning.By tightly focusing,the peak intensity exceeds 3.5 × 1020 W cm-2.These parameters predestine POLARIS as a scientific tool well suited for sophisticated experiments,as exemplified by presenting measurements of accelerated proton energies.Recently,an additional amplifier has been added to the laser chain.In the ramp-up phase,pulses from this amplifier are not yet compressed and have not yet reached the anticipated energy.Nevertheless,an output energy of 16.6 J has been achieved so far.展开更多
The Laboratory for Intense Lasers(L2I) is a research centre in optics and lasers dedicated to experimental research in high intensity laser science and technology and laser plasma interaction. Currently the laboratory...The Laboratory for Intense Lasers(L2I) is a research centre in optics and lasers dedicated to experimental research in high intensity laser science and technology and laser plasma interaction. Currently the laboratory is undergoing an upgrade with the goal of increasing the versatility of the laser systems available to the users, as well as increasing the pulse repetition rate. In this paper we review the current status of the laser research and development programme of this facility, namely the upgraded capability and the recent progress towards the installation of an ultrashort, diode-pumped OPCPA laser system.展开更多
We propose a novel model to explain the physical process of the thermally induced core laser leakage(TICLL) effect in a high power co-pumped ytterbium doped fiber(YDF) amplifier. This model considers the thermally ind...We propose a novel model to explain the physical process of the thermally induced core laser leakage(TICLL) effect in a high power co-pumped ytterbium doped fiber(YDF) amplifier. This model considers the thermally induced mode bending loss decrease and the thermally induced mode instability(TMI) in the coiled YDF, and is further used to reproduce the TICLL effect in the high power co-pumped step-index 20/400 fiber amplifier. Besides, the TICLL effect in the copumping scheme and counter-pumping scheme is compared. The result proves that the TICLL effect is caused by the combined effect of the thermally induced mode bending loss decrease and the TMI, and could be mitigated by adopting the counter-pumping scheme. To our best knowledge, this is the first theoretical explanation of the TICLL effect in high power fiber amplifier.展开更多
基金sponsored by the National Natural Science Foundation of China (Nos. 61705264 and 61705265)
文摘An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability(TMI) suppression. The stimulated Brillouin scattering(SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ～0.025, 0.17 and ～0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3times. The beam quality(M～2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the influence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering(SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multidetrimental effects(SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth fiber amplifiers.
文摘We present a lamp-pumped Nd： phosphate glass laser amplifier delivering up to 1 J of pulse energy at 1053 nm with a repetition rate of 1 Hz and an injected pulse energy of 2.5 mJ. The amplifier system employs a beamshaping module and a four-pass, lamp-pumped amplifier. The thermally induced wavefront distortion is mitigated and a uniform gain distribution is obtained by a four-lamp-pmnped laser head in the amplifier. Thus, an excellent beam quality is obtained.
基金supported by the National Natural Science Foundation of China(No.61505260)the National Key Research and Development Program of China(No.2016YFB0402204)
文摘Compared with traditional uniform fibers, tapered fiber has numerous unique advantages, such as larger mode area,higher pump absorption, suppression to nonlinear effects, and maintaining good beam quality. In this manuscript, we have constructed an all-fiberized fiber amplifier which is based on a piece of ytterbium-doped tapered double-clad fiber(T-DCF). The fiber amplifier is operated under continuous wave(CW) regime at 1080 nm wavelength. The M2 factor of the amplifier at 1.39 k W output power is ～1.8. The maximum output power of the system reached 1.47 k W, which, to the best of our knowledge, is the highest output power of long tapered fiber based fiber laser system. Our result successfully verifies the potential of power scalability and all-fiberized capability of long tapered fiber, and the performance of our system can be further enhanced by fiber design optimization.
基金supported by the project of the National Natural Science Foundation of China (grant numbers 61378007 and 61138005)
文摘A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durations of 3–5 ns and beam diameter 60 mm, employs a sequence of successive rod amplifiers to achieve 100-J-level energy at 1053 nm at3 ns. The frequency conversion can provide energy of 50-J level at 351 nm. In addition to the high stability of the energy output, the most valuable of the laser system is the high spatiotemporal beam quality of the output, which contains the uniform square pulse waveform, the uniform flat-top spatial fluence distribution and the uniform flat-top wavefront.
基金funded by the NEWTON China–UK Joint Research Project on Laser-driven Ion Acceleration and Novel Terahertz Radiation
文摘In this paper we review the design and development of a 100 J, 10 Hz nanosecond pulsed laser, codenamed DiPOLE100 X,being built at the Central Laser Facility(CLF). This 1 kW average power diode-pumped solid-state laser(DPSSL) is based on a master oscillator power amplifier(MOPA) design, which includes two cryogenic gas cooled amplifier stages based on DiPOLE multi-slab ceramic Yb:YAG amplifier technology developed at the CLF. The laser will produce pulses between 2 and 15 ns in duration with precise, arbitrarily selectable shapes, at pulse repetition rates up to 10 Hz, allowing real-time shape optimization for compression experiments. Once completed, the laser will be delivered to the European X-ray Free Electron Laser(XFEL) facility in Germany as a UK-funded contribution in kind, where it will be used to study extreme states of matter at the High Energy Density(HED) instrument.
基金supported by National Natural Science Foundation of China under Grant No.61405211
文摘Optical damages, which severely degrade the output energy performance of Nd:glass regenerative amplifiers, are discussed in detail in this paper. By a series of experiments, it has been confirmed that these damages result from laser-induced contamination. Based on this work, several improvements are made to boost output energy performance of the regenerative amplifier. The output energy of the regenerative amplifier after improvements declines 4% after 1000 h of operation, much less than it used to, 60% after 560 h of operation.
文摘近年来随着光电技术应用需求的增长,诸如平面激光诱导荧光技术、激光探测和激光加工等越来越多的领域展现出对高重频大能量的脉冲激光的需求。然而受激光器平均功率的限制,传统的连续脉冲模式的脉冲激光器难以实现高重频和大能量的兼顾输出。文中研究了一种LD泵浦Nd:YAG1.06μm脉冲串激光器及其放大系统。采用长脉冲泵浦、腔内调制和MOPA放大技术,实现了一段时间内激光器的高重频和大能量的兼顾输出。在调Q重频分别为10、50、100 k Hz时,脉冲串能量分别达到170.4、211.8、220.3 mJ,每串内分别包含2个、12个、25个脉冲,单脉冲能量分别为85.2、17.7、8.8 mJ。
基金funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No.654148 Laserlab-Europe
文摘We report on the energetic and beam quality performance of the second to the last main amplifier section HEPA I of the PENELOPE laser project. A polarization coupled double-12-pass scheme to verify the full amplification capacity of the last two amplifiers HEPA I and II was used. The small signal gain for a narrow-band continuous wave laser was 900 and 527 for a broadband nanosecond pulse, demonstrating 12.6 J of output pulse energy. Those pulses, being spectrally wide enough to support equivalent 150 fs long ultrashort pulses, are shown with an excellent spatial beam quality. A first active correction of the wavefront using a deformable mirror resulted in a Strehl ratio of 76% in the single-12-pass configuration for HEPA I.
基金funding from the European Commission’s (EC) 7th Framework Programme (LASERLAB-EUROPE,grant no.228334)from the Bundesministerium fr Bildung und Forschung (BMBF) (03ZIK445 and 03Z1H531)
文摘The development,the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed.Currently,the POLARIS system delivers 4 J energy,144 fs long laser pulses with an ultra-high temporal contrast of 5 × 1012 for the ASE,which is achieved using a so-called double chirped-pulse amplification scheme and cross-polarized wave generation pulse cleaning.By tightly focusing,the peak intensity exceeds 3.5 × 1020 W cm-2.These parameters predestine POLARIS as a scientific tool well suited for sophisticated experiments,as exemplified by presenting measurements of accelerated proton energies.Recently,an additional amplifier has been added to the laser chain.In the ramp-up phase,pulses from this amplifier are not yet compressed and have not yet reached the anticipated energy.Nevertheless,an output energy of 16.6 J has been achieved so far.
基金supported by Fundao para a Ciência e a Tecnologia,Laserlab-Europe(EC’s FP7,grant agreement no.284464)funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053
文摘The Laboratory for Intense Lasers(L2I) is a research centre in optics and lasers dedicated to experimental research in high intensity laser science and technology and laser plasma interaction. Currently the laboratory is undergoing an upgrade with the goal of increasing the versatility of the laser systems available to the users, as well as increasing the pulse repetition rate. In this paper we review the current status of the laser research and development programme of this facility, namely the upgraded capability and the recent progress towards the installation of an ultrashort, diode-pumped OPCPA laser system.
基金the support of National Natural Science Foundation of China(NSFC)(No.61605246)
文摘We propose a novel model to explain the physical process of the thermally induced core laser leakage(TICLL) effect in a high power co-pumped ytterbium doped fiber(YDF) amplifier. This model considers the thermally induced mode bending loss decrease and the thermally induced mode instability(TMI) in the coiled YDF, and is further used to reproduce the TICLL effect in the high power co-pumped step-index 20/400 fiber amplifier. Besides, the TICLL effect in the copumping scheme and counter-pumping scheme is compared. The result proves that the TICLL effect is caused by the combined effect of the thermally induced mode bending loss decrease and the TMI, and could be mitigated by adopting the counter-pumping scheme. To our best knowledge, this is the first theoretical explanation of the TICLL effect in high power fiber amplifier.
