The coronavirus disease 2019(COVID-19)pandemic has caused a surge in demand for face masks,with the massive consumption of masks leading to an increase in resource-related and environmental con-cerns.In this work,we f...The coronavirus disease 2019(COVID-19)pandemic has caused a surge in demand for face masks,with the massive consumption of masks leading to an increase in resource-related and environmental con-cerns.In this work,we fabricated meltblown polypropylene(mb-PP)-based high-performance planar face masks and investigated the effects of six commonly used disinfection methods and various mask-wearing periods on the reusability of these masks.The results show that,after three cycles of treatment using hot water at 70℃ for 30 min,which is one of the most scalable,user-friendly methods for viral disinfection,the particle filtration efficiency(PFE)of the mask remained almost unchanged.After mask wearing for 24 h and subsequent disinfection using the same treatment procedures,the PFE decreased to 91.3%;the average number of bacterial and fungal colonies was assessed to be 9.2 and 51.6 colony-forming units per gram(CFU∙g^(-1)),respectively;and coliform and pyogenic bacteria were not detected.Both the PFE and the microbial indicators are well above the standard for reusable masks after disinfection.Schlieren pho-tography was then used to assess the capabilities of used and disinfected masks during use;it showed that the masks exhibit a high performance in suppressing the spread of breathed air.展开更多
After reaching a world record of 10 PW,the peak power development of the titanium-sapphire(Ti:sapphire)PW ultraintense lasers has hit a bottleneck,and it seems to be difficult to continue increasing due to the difficu...After reaching a world record of 10 PW,the peak power development of the titanium-sapphire(Ti:sapphire)PW ultraintense lasers has hit a bottleneck,and it seems to be difficult to continue increasing due to the difficulty of manufacturing larger Ti:sapphire crystals and the limitation of parasitic lasing that can consume stored pump energy.Unlike coherent beam combining,coherent Ti:sapphire tiling is a viable solution for expanding Ti:sapphire crystal sizes,truncating transverse amplified spontaneous emission,suppressing parasitic lasing,and,importantly,not requiring complex space-time tiling control.A theoretical analysis of the above features and an experimental demonstration of high-quality laser amplification are reported.The results show that the addition of a 2×2 tiled Ti:sapphire amplifier to today’s 10 PW ultraintense laser is a viable technique to break the 10 PW limit and directly increase the highest peak power recorded by a factor of 4,further approaching the exawatt class.展开更多
Time-domain characterization of ultrashort pulses is essential for studying interactions between light and matter.Here,we propose and demonstrate an all-optical pulse sampling technique based on reflected four-wave mi...Time-domain characterization of ultrashort pulses is essential for studying interactions between light and matter.Here,we propose and demonstrate an all-optical pulse sampling technique based on reflected four-wave mixing with perturbation on a solid surface.In this method,a weak perturbation pulse perturbs the four-wave mixing signal generated by a strong fundamental pulse.The modulation signal of the four-wave mixing,which is detected in the reflection geometry to ensure a perfect phase-matching condition,directly reflects the temporal profile of the perturbation pulse.We successfully characterized multi-cycle and few-cycle pulses using this method.The reliability of our approach was verified by comparing it to the widely employed frequency-resolved optical gating method.This technique provides a simple and robust method for characterizing ultrashort laser pulses.展开更多
A novel tiled Ti:sapphire(Ti:S)amplifier was experimentally demonstrated with>1 J amplified chirped pulse output.Two Ti:S crystals having dimensions of 14 mm×14 mm×25 mm were tiled as the gain medium in a...A novel tiled Ti:sapphire(Ti:S)amplifier was experimentally demonstrated with>1 J amplified chirped pulse output.Two Ti:S crystals having dimensions of 14 mm×14 mm×25 mm were tiled as the gain medium in a four-pass amplifier.Maximum output energy of 1.18 J was obtained with 2.75 J pump energy.The energy conversion efficiency of the tiled Ti:S amplifier was comparable with a single Ti:S amplifier.The laser pulse having the maximum peak power of 28 TW was obtained after the compressor.Moreover,the influence of the beam gap on the far field was discussed.This novel tiled Ti:S amplifier technique can provide a potential way for 100 PW or EW lasers in the future.展开更多
Rapid advancements in high-energy ultrafast lasers and free electron lasers have made it possible to obtain extreme physical conditions in the laboratory, which lays the foundation for investigating the interaction be...Rapid advancements in high-energy ultrafast lasers and free electron lasers have made it possible to obtain extreme physical conditions in the laboratory, which lays the foundation for investigating the interaction between light and matter and probing ultrafast dynamic processes. High temporal resolution is a prerequisite for realizing the value of these largescale facilities. Here, we propose a new method that has the potential to enable the various subsystems of large scientific facilities to work together well, and the measurement accuracy and synchronization precision of timing jitter are greatly improved by combining a balanced optical cross-correlator(BOC) with near-field interferometry technology. Initially,we compressed a 0.8 ps laser pulse to 95 fs, which not only improved the measurement accuracy by 3.6 times but also increased the BOC synchronization precision from 8.3 fs root-mean-square(RMS) to 1.12 fs RMS. Subsequently, we successfully compensated the phase drift between the laser pulses to 189 as RMS by using the BOC for pre-correction and near-field interferometry technology for fine compensation. This method realizes the measurement and correction of the timing jitter of ps-level lasers with as-level accuracy, and has the potential to promote ultrafast dynamics detection and pump–probe experiments.展开更多
The development of high-intensity ultrafast laser facilities provides the possibility to create novel physical phenomena and matter states.The timing fluctuation of the laser pulses is crucial for pump–probe experime...The development of high-intensity ultrafast laser facilities provides the possibility to create novel physical phenomena and matter states.The timing fluctuation of the laser pulses is crucial for pump–probe experiments,which is one of the vital means to observe the ultrafast dynamics driven by intense laser pulses.In this paper,we demonstrate the timing fluctuation characterization and control of the front end of a 100-PW laser that is composed of a high-contrast optical parametric amplifier(seed)and a 200-TW optical parametric chirped pulse amplifier(preamplifier).By combining the timing jitter measurement with a feedback system,the laser seed and preamplifier are synchronized to the reference with timing fluctuations of 1.82 and 4.48 fs,respectively.The timing system will be a key prerequisite for the stable operation of 100-PW laser facilities and provide the basis for potential pump–probe experiments performed on the laser.展开更多
基金supported by National Key Research and Development Program of China (2020YFC0844800)the Science and Technology Planning Project of Beijing (Z201100007520006)
文摘The coronavirus disease 2019(COVID-19)pandemic has caused a surge in demand for face masks,with the massive consumption of masks leading to an increase in resource-related and environmental con-cerns.In this work,we fabricated meltblown polypropylene(mb-PP)-based high-performance planar face masks and investigated the effects of six commonly used disinfection methods and various mask-wearing periods on the reusability of these masks.The results show that,after three cycles of treatment using hot water at 70℃ for 30 min,which is one of the most scalable,user-friendly methods for viral disinfection,the particle filtration efficiency(PFE)of the mask remained almost unchanged.After mask wearing for 24 h and subsequent disinfection using the same treatment procedures,the PFE decreased to 91.3%;the average number of bacterial and fungal colonies was assessed to be 9.2 and 51.6 colony-forming units per gram(CFU∙g^(-1)),respectively;and coliform and pyogenic bacteria were not detected.Both the PFE and the microbial indicators are well above the standard for reusable masks after disinfection.Schlieren pho-tography was then used to assess the capabilities of used and disinfected masks during use;it showed that the masks exhibit a high performance in suppressing the spread of breathed air.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1604401)the Shanghai Science and Technology Committee Program(Grant Nos.22560780100 and 23560750200)the National Natural Science Foundation of China(Grant No.61925507).
文摘After reaching a world record of 10 PW,the peak power development of the titanium-sapphire(Ti:sapphire)PW ultraintense lasers has hit a bottleneck,and it seems to be difficult to continue increasing due to the difficulty of manufacturing larger Ti:sapphire crystals and the limitation of parasitic lasing that can consume stored pump energy.Unlike coherent beam combining,coherent Ti:sapphire tiling is a viable solution for expanding Ti:sapphire crystal sizes,truncating transverse amplified spontaneous emission,suppressing parasitic lasing,and,importantly,not requiring complex space-time tiling control.A theoretical analysis of the above features and an experimental demonstration of high-quality laser amplification are reported.The results show that the addition of a 2×2 tiled Ti:sapphire amplifier to today’s 10 PW ultraintense laser is a viable technique to break the 10 PW limit and directly increase the highest peak power recorded by a factor of 4,further approaching the exawatt class.
基金supported by the National Key R&D Program of China(No.2022YFE0111500)the National Natural Science Foundation of China(NSFC)(Nos.62175256,12104501,92050107 and 92250303)+5 种基金the Natural Science Basic Research Program of Shaanxi(No.2019JCW-03)the Science and Technology Program of Xi’an(No.202005YK01)the Young Scientist Basic Research Program of the Chinese Academy of Sciences(No.YSBR-091)the Key Deployment Research Program of XIOPM(No.S19-020-III)the Innovation Team in Shaanxi Province(No.J21-029-III)the Youth Innovation Promotion Association XIOPM-CAS(No.WCH2021002)。
文摘Time-domain characterization of ultrashort pulses is essential for studying interactions between light and matter.Here,we propose and demonstrate an all-optical pulse sampling technique based on reflected four-wave mixing with perturbation on a solid surface.In this method,a weak perturbation pulse perturbs the four-wave mixing signal generated by a strong fundamental pulse.The modulation signal of the four-wave mixing,which is detected in the reflection geometry to ensure a perfect phase-matching condition,directly reflects the temporal profile of the perturbation pulse.We successfully characterized multi-cycle and few-cycle pulses using this method.The reliability of our approach was verified by comparing it to the widely employed frequency-resolved optical gating method.This technique provides a simple and robust method for characterizing ultrashort laser pulses.
基金the National Key R&D Program of China(No.2017YFE0123700)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB1603)+2 种基金the National Natural Science Foundation of China(No.61925507)the Program of Shanghai Academic/Technology Research Leader(No.18XD1404200)the Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX02)。
文摘A novel tiled Ti:sapphire(Ti:S)amplifier was experimentally demonstrated with>1 J amplified chirped pulse output.Two Ti:S crystals having dimensions of 14 mm×14 mm×25 mm were tiled as the gain medium in a four-pass amplifier.Maximum output energy of 1.18 J was obtained with 2.75 J pump energy.The energy conversion efficiency of the tiled Ti:S amplifier was comparable with a single Ti:S amplifier.The laser pulse having the maximum peak power of 28 TW was obtained after the compressor.Moreover,the influence of the beam gap on the far field was discussed.This novel tiled Ti:S amplifier technique can provide a potential way for 100 PW or EW lasers in the future.
基金supported by the National Natural Science Foundation of China(Nos.12325409,12388102 and U23A6002)the CAS Project for Young Scientists in Basic Research(No.YSBR-059)+1 种基金the Zhangjiang Laboratory Construction and Operation Project(No.20DZ2210300)the Shanghai Pilot Program for Basic Research–Chinese Academy of Sciences,Shanghai Branch
文摘Rapid advancements in high-energy ultrafast lasers and free electron lasers have made it possible to obtain extreme physical conditions in the laboratory, which lays the foundation for investigating the interaction between light and matter and probing ultrafast dynamic processes. High temporal resolution is a prerequisite for realizing the value of these largescale facilities. Here, we propose a new method that has the potential to enable the various subsystems of large scientific facilities to work together well, and the measurement accuracy and synchronization precision of timing jitter are greatly improved by combining a balanced optical cross-correlator(BOC) with near-field interferometry technology. Initially,we compressed a 0.8 ps laser pulse to 95 fs, which not only improved the measurement accuracy by 3.6 times but also increased the BOC synchronization precision from 8.3 fs root-mean-square(RMS) to 1.12 fs RMS. Subsequently, we successfully compensated the phase drift between the laser pulses to 189 as RMS by using the BOC for pre-correction and near-field interferometry technology for fine compensation. This method realizes the measurement and correction of the timing jitter of ps-level lasers with as-level accuracy, and has the potential to promote ultrafast dynamics detection and pump–probe experiments.
基金supported by the Shanghai High Repetition Rate XFEL and Extreme Light Facility (SHINE) projectthe National Natural Science Foundation of China (62105346)+2 种基金the CAS Project for Young Scientists in Basic Research(YSBR-059)the 100 Talents Program of CASthe Basic Research Project of the Shanghai Science and Technology Innovation Action Plan (20JC1416000)
文摘The development of high-intensity ultrafast laser facilities provides the possibility to create novel physical phenomena and matter states.The timing fluctuation of the laser pulses is crucial for pump–probe experiments,which is one of the vital means to observe the ultrafast dynamics driven by intense laser pulses.In this paper,we demonstrate the timing fluctuation characterization and control of the front end of a 100-PW laser that is composed of a high-contrast optical parametric amplifier(seed)and a 200-TW optical parametric chirped pulse amplifier(preamplifier).By combining the timing jitter measurement with a feedback system,the laser seed and preamplifier are synchronized to the reference with timing fluctuations of 1.82 and 4.48 fs,respectively.The timing system will be a key prerequisite for the stable operation of 100-PW laser facilities and provide the basis for potential pump–probe experiments performed on the laser.
