Since the proof-of-principle demonstration of optical parametric amplification to efficiently amplify chirped laser pulses in 1992, optical parametric chirped pulse amplification(OPCPA) became the most promising met...Since the proof-of-principle demonstration of optical parametric amplification to efficiently amplify chirped laser pulses in 1992, optical parametric chirped pulse amplification(OPCPA) became the most promising method for the amplification of broadband optical pulses. In the meantime, we are witnessing an exciting progress in the development of powerful and ultrashort pulse laser systems that employ chirped pulse parametric amplifiers. The output power and pulse duration of these systems have ranged from a few gigawatts to hundreds of terawatts with a potential of tens of petawatts power level. Meanwhile, the output pulse duration based on optical parametric amplification has entered the range of fewoptical-cycle field. In this paper, we overview the basic principles, trends in development, and current state of the ultrashort and laser systems based on OPCPA, respectively.展开更多
Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to t...Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to the chirped signal pulse which propagated in a changeless direction straightforward,but the pump beam were deflected in space with time by passing through a KTN crystal,which was applied with varied driving voltage.The theories of phase matching of each chirped signal frequency based on pump beam deflection was analyzed detailedly.And the type-I amplification of chirped signal with 800 nm central wavelength and 20 nm bandwidth pumped by 532 nm in BBO crystal was simulated as a case in point.The simulation results showed that the spectral distribution of chirped signal pulse was almost the same as the initial form,i.e.,there was nearly no narrowing on the amplified spectrum by using of the scanning OPCPA based on pump beam deflection.In addition,the simulations demonstrated that it was worth minimizing the voltage deviation applied to KTN crystal as much as possible for the sake of better waveform,larger bandwidth and higher conversion efficiency of amplified signal pulse in the proposed scanning OPCPA.展开更多
We studied the evolution of wavefront aberration(WFA) of a signal beam during amplification in a Ti:sapphire chirped pulse amplification(CPA) system. The results verified that the WFA of the amplified laser beam has l...We studied the evolution of wavefront aberration(WFA) of a signal beam during amplification in a Ti:sapphire chirped pulse amplification(CPA) system. The results verified that the WFA of the amplified laser beam has little relation with the change of the pump beam energies. Transverse parasitic lasing that might occur in CPA hardly affects the wavefront of the signal beam. Thermal effects were also considered in this study, and the results show that the thermal effect cumulated in multiple amplification processes also has no obvious influence on the wavefront of the signal beam for a single-shot frequency. The results presented in this paper confirmed experimentally that the amplification in a Ti:sapphire CPA system has little impact on the WFA of the signal beam and it is very helpful for wavefront correction of single-shot PW and multi-PW laser systems based on Ti:sapphire.展开更多
A high-energy femtosecond all ytterbium fiber amplifier based on a chirped-pulse amplification(CPA) technique at a repetition rate of 1 MHz seeded by a dispersion-management mode-locked picosecond broadband oscillat...A high-energy femtosecond all ytterbium fiber amplifier based on a chirped-pulse amplification(CPA) technique at a repetition rate of 1 MHz seeded by a dispersion-management mode-locked picosecond broadband oscillator is studied.We find that the compressed pulse duration is dependent on the amplified energy,the pulse duration of 804 fs corresponds to the maximum amplified energy of 10.5 μJ,while the shortest pulse duration of 424 fs corresponds to the amplified energy of 6.75 μJ.The measured energy fluctuation is approximately 0.46% root mean square(RMS) over 2 h.The low-cost femtosecond fiber laser source with super-stability will be widely used in industrial micromachines,medical therapy,and scientific studies.展开更多
High-power ultrafast laser amplification based on a non-polarization maintaining fiber chirped pulse amplifier is demonstrated.The active polarization control technology based on the root-mean-square propagation(RMS-p...High-power ultrafast laser amplification based on a non-polarization maintaining fiber chirped pulse amplifier is demonstrated.The active polarization control technology based on the root-mean-square propagation(RMS-prop)algorithm is employed to guarantee a linearly polarized output from the system.A maximum output power of 402.3 W at a repetition rate of 80 MHz is realized with a polarization extinction ratio(PER)of>11.4 dB.In addition,the reliable operation of the system is verified by examining the stability and noise properties of the amplified laser.The M2factor of the laser beam at the highest output power is measured to be less than 1.15,indicating a diffraction-limited beam quality.Finally,the amplified laser pulse is temporally compressed to 755 fs with a highest average power of 273.8 W.This is the first time,to the best of our knowledge,that the active polarization control technology was introduced into the high-power ultrafast fiber amplifier.展开更多
An all-fiber high-power linearly polarized chirped pulse amplification(CPA)system is experimentally demonstrated.Through stretching the pulse duration to a full width of approximately 2 ns with two cascaded chirped fi...An all-fiber high-power linearly polarized chirped pulse amplification(CPA)system is experimentally demonstrated.Through stretching the pulse duration to a full width of approximately 2 ns with two cascaded chirped fiber Bragg gratings(CFBGs),a maximum average output power of 612 W is achieved from a high-gain Yb-doped fiber that has a core diameter of 20μm with a slope efficiency of approximately 68%at the repetition rate of 80 MHz.At the maximum output power,the polarization degree is 92.5%and the M^(2)factor of the output beam quality is approximately 1.29;the slight performance degradations are attributed to the thermal effects in the main amplifier.By optimizing the B-integral of the amplifier and finely adjusting the higher-order dispersion of one of the CFBGs,the pulse width is compressed to 863 fs at the highest power with a compression efficiency of 72%,corresponding to a maximum compressed average power of 440.6 W,single pulse energy of 5.5μJ and peak power of about 4.67 MW.To the best of our knowledge,this is the highest average power of a femtosecond laser directly generated from an all-fiber linearly polarized CPA system.展开更多
In this work,a high-energy and high peak power chirped pulse amplifcation system with near difraction-limited beam quality based on tapered confned-doped fber(TCF)is experimentally demonstrated.The TCF has a core nume...In this work,a high-energy and high peak power chirped pulse amplifcation system with near difraction-limited beam quality based on tapered confned-doped fber(TCF)is experimentally demonstrated.The TCF has a core numerical aperture of 0.07 with core/cladding diameter of 35/250µm at the thin end and 56/400μm at the thick end.With a backward-pumping confguration,a maximum single pulse energy of 177.9μJ at a repetition rate of 504 kHz is realized,corresponding to an average power of 89.7 W.Through partially compensating for the accumulated nonlinear phase during the amplifcation process via adjusting the high order dispersion of the stretching chirped fber Bragg grating,the duration of the amplifed pulse is compressed to 401 fs with a pulse energy of 126.3μJ and a peak power of 207 MW,which to the best of our knowledge represents the highest peak power ever reported from a monolithic ultrafast fber laser.At the highest energy,the polarization extinction ratio and the M2 factor were respectively measured to be~19 dB and 1.20.In addition,the corresponding intensity noise properties as well as the short-and long-term stability were also examined,verifying a stable operation of the system.It is believed that the demonstrated laser source could fnd important applications in,for example,advanced manufacturing and photomedicine.展开更多
A high-power all polarization-maintaining(PM) chirped pulse amplification(CPA) system operating in the 2.0 μm range is experimentally demonstrated.Large mode area(LMA) thulium-doped fiber(TDF) with a core/cladding di...A high-power all polarization-maintaining(PM) chirped pulse amplification(CPA) system operating in the 2.0 μm range is experimentally demonstrated.Large mode area(LMA) thulium-doped fiber(TDF) with a core/cladding diameter of25/400 μm is employed to construct the main amplifier.Through dedicated coiling and cooling of the LMA-TDF to manage the loss of the higher order mode and thermal effect,a maximum average power of 314 W with a slope efficiency of 52% and polarization extinction ratio of 20 dB is realized.The pulse duration is compressed to 283 fs with a grating pair,corresponding to a calculated peak power of 10.8 MW,considering the compression efficiency of 88% and the estimated Strehl ratio of 89%.Moreover,through characterizing the noise properties of the laser,an integrated relative intensity noise of 0.11% at 100 Hz-1 MHz is obtained at the maximum output power,whereas the laser timing jitter is degraded by the final amplifier from 318 to 410 fs at an integration frequency of 5 kHz to 1 MHz,owing to the self-phase modulation effect-induced spectrum broadening.The root-mean-square of long-term power fluctuation is tested to be0.6%,verifying the good stability of the laser operation.To the best of our knowledge,this is the highest average power of an ultrafast laser realized from an all-PM-fiber TDF-CPA system ever reported.展开更多
It is well-known that the chirped pulse amplification(CPA) technique won the award for the 2018 Nobel Prize in Physics to Mourou and Strickland. The compression and stretching using gratings is the essence of the CPA ...It is well-known that the chirped pulse amplification(CPA) technique won the award for the 2018 Nobel Prize in Physics to Mourou and Strickland. The compression and stretching using gratings is the essence of the CPA technique for amplifying femtosecond laser pulses. It seems the public is less aware that there are also other structures for compression and stretching of femtosecond laser pulses using other diffractive gratings, such as doubled-density gratings and deep-etched gratings. Therefore, from the view of diffractive optics, the CPA technique is reviewed with different approaches and experimental implementations that are not only useful for a more comprehensive retrospective overview of CPA, but also for the prospective of the CPA technique,which might lead us to new areas of picometer and femtometer optics in the future.展开更多
We report the generation of high energy 2μm picosecond pulses from a thulium-doped fiber master oscillator power amplifier system.The all-fiber configuration was realized by a flexible large-mode area photonic crysta...We report the generation of high energy 2μm picosecond pulses from a thulium-doped fiber master oscillator power amplifier system.The all-fiber configuration was realized by a flexible large-mode area photonic crystal fiber(LMA-PCF).The amplifier output is a linearly-polarized 1.5 ns,100 kHz pulse train with a pulse energy of up to 250μJ.Pulse compression was achieved with(2+2)-pass chirped volume Bragg grating(CVBG)to obtain a 2.8 ps pulse width with a total pulse energy of 46μJ.The overall system compactness was enabled by the all-fiber amplifier design and the multi-pass CVBG-based compressor.The laser output was then used to demonstrate high-speed direct-writing capability on a temperature-sensitive biomaterial to change its topography(i.e.fabricate microchannels,foams and pores).The topographical modifications of biomaterials are known to influence cell behavior and fate which is potentially useful in many cell and tissue engineering applications.展开更多
We present the performance of a high-power Nd:glass laser system,which produces a 1.1 J,250 fs,7.3 nm broadband laser pulse based on the combination of optical parametric amplification(OPA) and chirped pulse amplifica...We present the performance of a high-power Nd:glass laser system,which produces a 1.1 J,250 fs,7.3 nm broadband laser pulse based on the combination of optical parametric amplification(OPA) and chirped pulse amplification(CPA).The two-stage OPA provides broadband seed pulses for the three-stage Nd:glass amplifiers based on the technology of CPA.Compared to the conventional oscillator seed source,the most important advantage of such a seed source supplied by the two-stage OPA is that it possesses the capacities of broad bandwidth and high energy.展开更多
We demonstrate a high-contrast, joule-level Nd:glass laser system operating at 0.5 Hz repetition rate based on a double chirped pulse amplification(CPA) scheme. By injecting high-contrast, high-energy seed pulses into...We demonstrate a high-contrast, joule-level Nd:glass laser system operating at 0.5 Hz repetition rate based on a double chirped pulse amplification(CPA) scheme. By injecting high-contrast, high-energy seed pulses into the Nd:glass CPA stage, the pulse energy is amplified to 1.9 J through two optical parametric CPA stages and two Nd:glass amplifiers. The temporal contrast of compressed pulse is measured down to the level of 10^(-8)at tens of ps, and 10^(-10) near 200 ps before the main pulse, respectively.展开更多
We develop a splicing technology of Ti:sapphire crystals for a high-energy chirped pulse amplifier laser system that can suppress the parasitic lasing to improve the amplification efficiency compared to a large-size s...We develop a splicing technology of Ti:sapphire crystals for a high-energy chirped pulse amplifier laser system that can suppress the parasitic lasing to improve the amplification efficiency compared to a large-size single Ti:sapphire crystal amplifier. Theoretical investigations on the characteristics of the amplifier with four splicing Ti:sapphire crystals,such as parasitic-lasing suppression and amplification efficiencies, are carried out. Some possible issues resulting from this splicing technology, including spectral modulation, stretching or splitting of the temporal profile, and the sidelobe generation in the spatial domain(near field and far field), are also investigated. Moreover, the feasibility of the splicing technology is preliminarily demonstrated in an experiment with a small splicing Ti:sapphire crystals amplifier. The temporal profile and spatial distribution of the output pulse from the splicing Ti:sapphire crystal amplifier are discussed in relation to the output pulse from a single Ti:sapphire crystal amplifier.展开更多
The experiment of the generation and amplification of femetosecond Ti:sapphire laser pulse at high repetition rate is reported. The laser pulses with minimum pulsewidth 15 fs, maximum spectrum width of 80 nm, average ...The experiment of the generation and amplification of femetosecond Ti:sapphire laser pulse at high repetition rate is reported. The laser pulses with minimum pulsewidth 15 fs, maximum spectrum width of 80 nm, average power of 200 mW are generated from a home-built self-mode-locked Ti:sapphire laser. As a seed pulse which is selected from the oscillator, the laser pulse is further amplified by using chirped-pulse-amplification technology in a Ti:sapphire amplifier from which a kind of pulses with single-pulse-energy of 100 uj, pulsewidth after compressing of 50 fs at 5 kHz repetition rate are produced. The system design and experimental results are discussed.展开更多
We report on our high-contrast laser based on high-contrast, high-energy seed injection, low-gain optical para- metric chirped pulse amplification (OPCPA), and Nd:glass amplifiers, which can be used as the high-con...We report on our high-contrast laser based on high-contrast, high-energy seed injection, low-gain optical para- metric chirped pulse amplification (OPCPA), and Nd:glass amplifiers, which can be used as the high-contrast front end of a high-power Nd:glass chirped pulse amplification (CPA) laser system. The energy of the stretched 1053 nm high-contrast seed pulse increases to 60 DJ by optimizing the frequency doubling crystal in the pulse cleaning device. After passing through a two-stage low-gain OPCPA, a 2-pass 2-rod Nd:glass amplifier, and a compressor the amplified pulse of 131 mJ/282 fs is achieved. The third-order correlation scanning measurement shows that the pulse contrast in the tens of ps range is about 10^-7-10^-8. With the high-contrast seed passing through the stretcher and compressor only, the contrast measurement indicates that the stretching-compressing process leads mainly to the contrast degradation of the amplified pulse.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61378030 and 11127901)the National Basic Research Program of China(Grant No.2011CB808101)the International S&T Cooperation Program of China(Grant No.2011DFA11300)
文摘Since the proof-of-principle demonstration of optical parametric amplification to efficiently amplify chirped laser pulses in 1992, optical parametric chirped pulse amplification(OPCPA) became the most promising method for the amplification of broadband optical pulses. In the meantime, we are witnessing an exciting progress in the development of powerful and ultrashort pulse laser systems that employ chirped pulse parametric amplifiers. The output power and pulse duration of these systems have ranged from a few gigawatts to hundreds of terawatts with a potential of tens of petawatts power level. Meanwhile, the output pulse duration based on optical parametric amplification has entered the range of fewoptical-cycle field. In this paper, we overview the basic principles, trends in development, and current state of the ultrashort and laser systems based on OPCPA, respectively.
基金supported by Science and Technology Innovation Seedling Project of Sichuan Province,China(Grant No.2018100)Major Project of CDNU(Grant No.CS18ZDZ0511).
文摘Combined with the optical beam deflection,a novel approach of phase matched broadband scanning optical parametric chirped pulse amplification(OPCPA)was proposed.For this scheme,there was no superfluous operations to the chirped signal pulse which propagated in a changeless direction straightforward,but the pump beam were deflected in space with time by passing through a KTN crystal,which was applied with varied driving voltage.The theories of phase matching of each chirped signal frequency based on pump beam deflection was analyzed detailedly.And the type-I amplification of chirped signal with 800 nm central wavelength and 20 nm bandwidth pumped by 532 nm in BBO crystal was simulated as a case in point.The simulation results showed that the spectral distribution of chirped signal pulse was almost the same as the initial form,i.e.,there was nearly no narrowing on the amplified spectrum by using of the scanning OPCPA based on pump beam deflection.In addition,the simulations demonstrated that it was worth minimizing the voltage deviation applied to KTN crystal as much as possible for the sake of better waveform,larger bandwidth and higher conversion efficiency of amplified signal pulse in the proposed scanning OPCPA.
基金Project supported by the National Natural Science Foundation of China(Grant No.61775223)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB1603)
文摘We studied the evolution of wavefront aberration(WFA) of a signal beam during amplification in a Ti:sapphire chirped pulse amplification(CPA) system. The results verified that the WFA of the amplified laser beam has little relation with the change of the pump beam energies. Transverse parasitic lasing that might occur in CPA hardly affects the wavefront of the signal beam. Thermal effects were also considered in this study, and the results show that the thermal effect cumulated in multiple amplification processes also has no obvious influence on the wavefront of the signal beam for a single-shot frequency. The results presented in this paper confirmed experimentally that the amplification in a Ti:sapphire CPA system has little impact on the WFA of the signal beam and it is very helpful for wavefront correction of single-shot PW and multi-PW laser systems based on Ti:sapphire.
基金Project supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2012BAC23B03)the National Key Basic Research Program of China(Grant No.2013CB922401)the National Natural Science Foundation of China(Grant No.11474002)
文摘A high-energy femtosecond all ytterbium fiber amplifier based on a chirped-pulse amplification(CPA) technique at a repetition rate of 1 MHz seeded by a dispersion-management mode-locked picosecond broadband oscillator is studied.We find that the compressed pulse duration is dependent on the amplified energy,the pulse duration of 804 fs corresponds to the maximum amplified energy of 10.5 μJ,while the shortest pulse duration of 424 fs corresponds to the amplified energy of 6.75 μJ.The measured energy fluctuation is approximately 0.46% root mean square(RMS) over 2 h.The low-cost femtosecond fiber laser source with super-stability will be widely used in industrial micromachines,medical therapy,and scientific studies.
基金supported by the Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.QL20220007)。
文摘High-power ultrafast laser amplification based on a non-polarization maintaining fiber chirped pulse amplifier is demonstrated.The active polarization control technology based on the root-mean-square propagation(RMS-prop)algorithm is employed to guarantee a linearly polarized output from the system.A maximum output power of 402.3 W at a repetition rate of 80 MHz is realized with a polarization extinction ratio(PER)of>11.4 dB.In addition,the reliable operation of the system is verified by examining the stability and noise properties of the amplified laser.The M2factor of the laser beam at the highest output power is measured to be less than 1.15,indicating a diffraction-limited beam quality.Finally,the amplified laser pulse is temporally compressed to 755 fs with a highest average power of 273.8 W.This is the first time,to the best of our knowledge,that the active polarization control technology was introduced into the high-power ultrafast fiber amplifier.
基金This work was supported by the National Natural Science Foundation of China(No.62005316)Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02).
文摘An all-fiber high-power linearly polarized chirped pulse amplification(CPA)system is experimentally demonstrated.Through stretching the pulse duration to a full width of approximately 2 ns with two cascaded chirped fiber Bragg gratings(CFBGs),a maximum average output power of 612 W is achieved from a high-gain Yb-doped fiber that has a core diameter of 20μm with a slope efficiency of approximately 68%at the repetition rate of 80 MHz.At the maximum output power,the polarization degree is 92.5%and the M^(2)factor of the output beam quality is approximately 1.29;the slight performance degradations are attributed to the thermal effects in the main amplifier.By optimizing the B-integral of the amplifier and finely adjusting the higher-order dispersion of one of the CFBGs,the pulse width is compressed to 863 fs at the highest power with a compression efficiency of 72%,corresponding to a maximum compressed average power of 440.6 W,single pulse energy of 5.5μJ and peak power of about 4.67 MW.To the best of our knowledge,this is the highest average power of a femtosecond laser directly generated from an all-fiber linearly polarized CPA system.
基金the Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02)the Postgraduate Scientifc Research Innovation Project of Hunan Province(No.QL20220007).
文摘In this work,a high-energy and high peak power chirped pulse amplifcation system with near difraction-limited beam quality based on tapered confned-doped fber(TCF)is experimentally demonstrated.The TCF has a core numerical aperture of 0.07 with core/cladding diameter of 35/250µm at the thin end and 56/400μm at the thick end.With a backward-pumping confguration,a maximum single pulse energy of 177.9μJ at a repetition rate of 504 kHz is realized,corresponding to an average power of 89.7 W.Through partially compensating for the accumulated nonlinear phase during the amplifcation process via adjusting the high order dispersion of the stretching chirped fber Bragg grating,the duration of the amplifed pulse is compressed to 401 fs with a pulse energy of 126.3μJ and a peak power of 207 MW,which to the best of our knowledge represents the highest peak power ever reported from a monolithic ultrafast fber laser.At the highest energy,the polarization extinction ratio and the M2 factor were respectively measured to be~19 dB and 1.20.In addition,the corresponding intensity noise properties as well as the short-and long-term stability were also examined,verifying a stable operation of the system.It is believed that the demonstrated laser source could fnd important applications in,for example,advanced manufacturing and photomedicine.
基金supported by the Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2020ZR02)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.QL20210015).
文摘A high-power all polarization-maintaining(PM) chirped pulse amplification(CPA) system operating in the 2.0 μm range is experimentally demonstrated.Large mode area(LMA) thulium-doped fiber(TDF) with a core/cladding diameter of25/400 μm is employed to construct the main amplifier.Through dedicated coiling and cooling of the LMA-TDF to manage the loss of the higher order mode and thermal effect,a maximum average power of 314 W with a slope efficiency of 52% and polarization extinction ratio of 20 dB is realized.The pulse duration is compressed to 283 fs with a grating pair,corresponding to a calculated peak power of 10.8 MW,considering the compression efficiency of 88% and the estimated Strehl ratio of 89%.Moreover,through characterizing the noise properties of the laser,an integrated relative intensity noise of 0.11% at 100 Hz-1 MHz is obtained at the maximum output power,whereas the laser timing jitter is degraded by the final amplifier from 318 to 410 fs at an integration frequency of 5 kHz to 1 MHz,owing to the self-phase modulation effect-induced spectrum broadening.The root-mean-square of long-term power fluctuation is tested to be0.6%,verifying the good stability of the laser operation.To the best of our knowledge,this is the highest average power of an ultrafast laser realized from an all-PM-fiber TDF-CPA system ever reported.
基金supported by the Shanghai Science and Technology Committee (No. 19JC1415400)the National Key Research and Development Program of China(No. 2019YFF0216402)the Cutting-Edge Sciences Important Research Program,Chinese Academy of Sciences (No. QYZDJ-SSW-JSC014)。
文摘It is well-known that the chirped pulse amplification(CPA) technique won the award for the 2018 Nobel Prize in Physics to Mourou and Strickland. The compression and stretching using gratings is the essence of the CPA technique for amplifying femtosecond laser pulses. It seems the public is less aware that there are also other structures for compression and stretching of femtosecond laser pulses using other diffractive gratings, such as doubled-density gratings and deep-etched gratings. Therefore, from the view of diffractive optics, the CPA technique is reviewed with different approaches and experimental implementations that are not only useful for a more comprehensive retrospective overview of CPA, but also for the prospective of the CPA technique,which might lead us to new areas of picometer and femtometer optics in the future.
基金Agency for Science,Technology and Research(A^*STAR)Singapore through the X-ray Photonics Programme(1426500052)A^*STAR Graduate Academy through the A^*STAR Graduate Scholarship.
文摘We report the generation of high energy 2μm picosecond pulses from a thulium-doped fiber master oscillator power amplifier system.The all-fiber configuration was realized by a flexible large-mode area photonic crystal fiber(LMA-PCF).The amplifier output is a linearly-polarized 1.5 ns,100 kHz pulse train with a pulse energy of up to 250μJ.Pulse compression was achieved with(2+2)-pass chirped volume Bragg grating(CVBG)to obtain a 2.8 ps pulse width with a total pulse energy of 46μJ.The overall system compactness was enabled by the all-fiber amplifier design and the multi-pass CVBG-based compressor.The laser output was then used to demonstrate high-speed direct-writing capability on a temperature-sensitive biomaterial to change its topography(i.e.fabricate microchannels,foams and pores).The topographical modifications of biomaterials are known to influence cell behavior and fate which is potentially useful in many cell and tissue engineering applications.
基金supported by the National Natural Science Foundation of China (Grant No.60890202)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20110161110012)+1 种基金the Department of Science and Technology of Hunan Province (Grant No.2011FJ3121)the Fundamental Research Funds for the Central Universities,Hunan University and SRF for ROCS,SEM
文摘We present the performance of a high-power Nd:glass laser system,which produces a 1.1 J,250 fs,7.3 nm broadband laser pulse based on the combination of optical parametric amplification(OPA) and chirped pulse amplification(CPA).The two-stage OPA provides broadband seed pulses for the three-stage Nd:glass amplifiers based on the technology of CPA.Compared to the conventional oscillator seed source,the most important advantage of such a seed source supplied by the two-stage OPA is that it possesses the capacities of broad bandwidth and high energy.
文摘We demonstrate a high-contrast, joule-level Nd:glass laser system operating at 0.5 Hz repetition rate based on a double chirped pulse amplification(CPA) scheme. By injecting high-contrast, high-energy seed pulses into the Nd:glass CPA stage, the pulse energy is amplified to 1.9 J through two optical parametric CPA stages and two Nd:glass amplifiers. The temporal contrast of compressed pulse is measured down to the level of 10^(-8)at tens of ps, and 10^(-10) near 200 ps before the main pulse, respectively.
基金partially supported by the National Basic Research Program of China (Grant No. 2011CB808101)the National Natural Science Foundation of China (NSFC) (Grant Nos. 61221064, 61078037, 11127901, 11134010)the International S&T Cooperation Program of China (Grant No. 2011DFA11300)
文摘We develop a splicing technology of Ti:sapphire crystals for a high-energy chirped pulse amplifier laser system that can suppress the parasitic lasing to improve the amplification efficiency compared to a large-size single Ti:sapphire crystal amplifier. Theoretical investigations on the characteristics of the amplifier with four splicing Ti:sapphire crystals,such as parasitic-lasing suppression and amplification efficiencies, are carried out. Some possible issues resulting from this splicing technology, including spectral modulation, stretching or splitting of the temporal profile, and the sidelobe generation in the spatial domain(near field and far field), are also investigated. Moreover, the feasibility of the splicing technology is preliminarily demonstrated in an experiment with a small splicing Ti:sapphire crystals amplifier. The temporal profile and spatial distribution of the output pulse from the splicing Ti:sapphire crystal amplifier are discussed in relation to the output pulse from a single Ti:sapphire crystal amplifier.
文摘The experiment of the generation and amplification of femetosecond Ti:sapphire laser pulse at high repetition rate is reported. The laser pulses with minimum pulsewidth 15 fs, maximum spectrum width of 80 nm, average power of 200 mW are generated from a home-built self-mode-locked Ti:sapphire laser. As a seed pulse which is selected from the oscillator, the laser pulse is further amplified by using chirped-pulse-amplification technology in a Ti:sapphire amplifier from which a kind of pulses with single-pulse-energy of 100 uj, pulsewidth after compressing of 50 fs at 5 kHz repetition rate are produced. The system design and experimental results are discussed.
文摘We report on our high-contrast laser based on high-contrast, high-energy seed injection, low-gain optical para- metric chirped pulse amplification (OPCPA), and Nd:glass amplifiers, which can be used as the high-contrast front end of a high-power Nd:glass chirped pulse amplification (CPA) laser system. The energy of the stretched 1053 nm high-contrast seed pulse increases to 60 DJ by optimizing the frequency doubling crystal in the pulse cleaning device. After passing through a two-stage low-gain OPCPA, a 2-pass 2-rod Nd:glass amplifier, and a compressor the amplified pulse of 131 mJ/282 fs is achieved. The third-order correlation scanning measurement shows that the pulse contrast in the tens of ps range is about 10^-7-10^-8. With the high-contrast seed passing through the stretcher and compressor only, the contrast measurement indicates that the stretching-compressing process leads mainly to the contrast degradation of the amplified pulse.