The aim of this study was to explore the neuroprotective effect and mechanism of DHA on cerebral ischemia injury and blood-brain barrier(BBB)disruption.the focal cerebral I/R model was established by middle cerebral a...The aim of this study was to explore the neuroprotective effect and mechanism of DHA on cerebral ischemia injury and blood-brain barrier(BBB)disruption.the focal cerebral I/R model was established by middle cerebral artery oclusion(MCAO).BBB permeability was assessed with the leaking amount of Evans Blue and the expression of occludin and ZO-1.The expression of pyrin domain containing(NLRP3)was checked to explore the inhibition of inflammation by DHA.The results showed that DHA could significantly reduce cortical and sub-cortical infarct volumes,neurologic de ficit scores,cerebral edema,BBB permeability after I/R injury.Leaking amount of Evans Blue was reduced by DHA,and occludin and ZO-1 were up-regulated by DHA.The expression of NLRP3 was inhibited after exposure of DHA.Our results indicated that DHA could effectively penetrate the brain of MCAO rats,aleviated the I/R injury by inhibiting NLRP3 inflammasomes and improve BBB disruption,showing a great clinical potential for stroke.展开更多
Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train...Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise,so as to make sure that it is stable and resistant to noise.Here,in a series of carefully designed experiments,we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically modelocked at GHz frequencies to the acoustic resonance in a photonic crystal fiber(PCF)core.We characterize the selfdriven optomechanical lattice,which is distributed along the PCF and provides the structure that supports harmonic mode-locking,using a homodyne setup.We reveal that,after an abrupt perturbation,each soliton in the lattice undergoes damped oscillatory retiming within its trapping potential,while the retiming is strongly coupled to soliton dissipation.In addition,we show,through statistical analysis of the intra-cavity pulse spacing,how the trapping potentials are effective for suppressing timing jtter.The measurements and the theory developed in this work lay the groundwork for studies of the general stability and noise performance of harmonically mode-locked lasers as well as providing valuable insight into generic multi-pulse phenomena in mode-locked lasers.展开更多
An attosecond light source provides an advanced tool for investigating electron motion using time-resolvedspectroscopy techniques.Isolated attosecond pulses,especially,will significantlyadvance the study of electron d...An attosecond light source provides an advanced tool for investigating electron motion using time-resolvedspectroscopy techniques.Isolated attosecond pulses,especially,will significantlyadvance the study of electron dynamics.However,achieving high-intensity isolated attosecond pulses is still challenging at the present stage.In this paper,we propose a novel scheme for generating high-intensity,isolated attosecond soft x-ray free-electron lasers(FELs)using a mid-infrared(MiR)subcycle modulation laser from gas-filled hollow capillary fibers.The multi-cycle MlR pulses are first compressed to subcycles using a krypton-filled hollow capillary fiber with a decreasing pressure gradient due to the soliton self-compression effect.By utilizing such subcycle MlR laser pulses to modulate an electron beam,we can obtain a quasi-isolated current peak,which can then produce an isolated FEL pulse with a high signal-to-noise ratio,naturally synchronizing with the subcycle MiR laser pulse.Numerical simulations have been carried out,including subcycle pulse generation,electron beam modulation,and FEL radiation processes.The simulation results indicate that an isolated attosecond pulse with a wavelength of 1 nm,a peak power of~28 GW,a pulse duration of~580 as,and a signal-to-noise ratio of~96.2%can be generated by our proposed method.The numerical results demonstrated here pave a new way for generating a high-intensity isolated attosecond soft x-ray pulse,which may have many applications in nonlinear spectroscopy and atomic-site electronic processes.展开更多
We presented a repetition-rate tunable Yb-doped fiber laser system,which used a chirped fiber Bragg grating as a fiber stretcher designed to match the second-and third-order dispersion of the transmission grating comp...We presented a repetition-rate tunable Yb-doped fiber laser system,which used a chirped fiber Bragg grating as a fiber stretcher designed to match the second-and third-order dispersion of the transmission grating compressor.The system delivered 1-μJ,143-fs pulses at a 2 MHz repetition rate and 10-μJ,157-fs pulses at a 200 kHz repetition rate,respectively.The pulse repetition rate can be tuned from 200 kHz to 2 MHz while the pulse duration maintains<180 fs.This compact fiber laser source was built for applications in ophthalmology,such as corneal flap cutting and tissue vaporization.Furthermore,it can be applied in micro-machining applications,such as laser marking,scribing,and drilling.展开更多
Continuous-wave mode-locking at multi-GHz repetition rates is achieved in an ultrashort laser cavity at critical pulse energies 100 times lower than predicted by conventional theory.The authors reveal that dynamic gai...Continuous-wave mode-locking at multi-GHz repetition rates is achieved in an ultrashort laser cavity at critical pulse energies 100 times lower than predicted by conventional theory.The authors reveal that dynamic gain depletion and recovery between consecutive round-trips is the key factor behind a low-pulse-energy transition from Q-switched mode-locking(QSML)to continuous-wave mode-locking(CWML).As well as providing new insight into gain dynamics,the results suggest a practical route to low-threshold lasing at very high-repetition rates.展开更多
We present the flexible delivery of picosecond laser pulses with up to 20 W average power over a 3-m-long sample of antiresonant hollow-core fiber(AR-HCF)for laser-micromachining applications.Our experiments highlight...We present the flexible delivery of picosecond laser pulses with up to 20 W average power over a 3-m-long sample of antiresonant hollow-core fiber(AR-HCF)for laser-micromachining applications.Our experiments highlight the importance of optical-mode purity of the AR-HCF for manufacturing precision.We demonstrate that compared with an AR-HCF sample with a capillary to core(d/D)ratio of approximately 0.5,the AR-HCF with a d/D ratio of approximately 0.68 exhibits better capability of high-order-mode suppression,giving rise to improved micromachining quality.Moreover,the AR-HCF delivery system exhibits better pointing stability and setup flexibility than the free-space beam delivery system.These results pave the way to practical applications of AR-HCF in developing advanced equipment for ultrafast laser micromachining.展开更多
Mode-locked lasers have been widely used to explore interactions between optical solitons,including bound-soliton states that may be regarded as“photonic molecules”.Conventional mode-locked lasers normally,however,h...Mode-locked lasers have been widely used to explore interactions between optical solitons,including bound-soliton states that may be regarded as“photonic molecules”.Conventional mode-locked lasers normally,however,host at most only a few solitons,which means that stochastic behaviours involving large numbers of solitons cannot easily be studied under controlled experimental conditions.Here we report the use of an optoacoustically mode-locked fibre laser to create hundreds of temporal traps or“reactors”in parallel,within each of which multiple solitons can be isolated and controlled both globally and individually using all-optical methods.We achieve on-demand synthesis and dissociation of soliton molecules within these reactors,in this way unfolding a novel panorama of diverse dynamics in which the statistics of multi-soliton interactions can be studied.The results are of crucial importance in understanding dynamical soliton interactions and may motivate potential applications for all-optical control of ultrafast light fields in optical resonators.展开更多
Brain-inspired computing is a new technology that draws on the principles of brain science and is oriented to the efficient development of artificial general intelligence(AGI),and a brain-inspired computing system is ...Brain-inspired computing is a new technology that draws on the principles of brain science and is oriented to the efficient development of artificial general intelligence(AGI),and a brain-inspired computing system is a hierarchical system composed of neuromorphic chips,basic software and hardware,and algorithms/applications that embody this tech-nology.While the system is developing rapidly,it faces various challenges and opportunities brought by interdisciplinary research,including the issue of software and hardware fragmentation.This paper analyzes the status quo of brain-inspired computing systems.Enlightened by some design principle and methodology of general-purpose computers,it is proposed to construct"general-purpose"brain-inspired computing systems.A general-purpose brain-inspired computing system refers to a brain-inspired computing hierarchy constructed based on the design philosophy of decoupling software and hardware,which can flexibly support various brain-inspired computing applications and neuromorphic chips with different architec-tures.Further,this paper introduces our recent work in these aspects,including the ANN(artificial neural network)/SNN(spiking neural network)development tools,the hardware agnostic compilation infrastructure,and the chip micro-archi-tecture with high flexibility of programming and high performance;these studies show that the"general-purpose"system can remarkably improve the efficiency of application development and enhance the productivity of basic software,thereby being conductive to accelerating the advancement of various brain-inspired algorithms and applications.We believe that this is the key to the collaborative research and development,and the evolution of applications,basic software and chips in this field,and conducive to building a favorable software/hardware ecosystem of brain-inspired computing.展开更多
文摘The aim of this study was to explore the neuroprotective effect and mechanism of DHA on cerebral ischemia injury and blood-brain barrier(BBB)disruption.the focal cerebral I/R model was established by middle cerebral artery oclusion(MCAO).BBB permeability was assessed with the leaking amount of Evans Blue and the expression of occludin and ZO-1.The expression of pyrin domain containing(NLRP3)was checked to explore the inhibition of inflammation by DHA.The results showed that DHA could significantly reduce cortical and sub-cortical infarct volumes,neurologic de ficit scores,cerebral edema,BBB permeability after I/R injury.Leaking amount of Evans Blue was reduced by DHA,and occludin and ZO-1 were up-regulated by DHA.The expression of NLRP3 was inhibited after exposure of DHA.Our results indicated that DHA could effectively penetrate the brain of MCAO rats,aleviated the I/R injury by inhibiting NLRP3 inflammasomes and improve BBB disruption,showing a great clinical potential for stroke.
基金supported by the National Natural Science Foundation of China(Grant No.62375275 and 62275254)by Strategic Priority Research Program of the Chinese Academy of Science(XDB0650000)+1 种基金by Shanghai Science and Technology Plan Project Funding(Grant No.23JC1410100)by Fuyang High-level Talent Group Project.
文摘Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise,so as to make sure that it is stable and resistant to noise.Here,in a series of carefully designed experiments,we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically modelocked at GHz frequencies to the acoustic resonance in a photonic crystal fiber(PCF)core.We characterize the selfdriven optomechanical lattice,which is distributed along the PCF and provides the structure that supports harmonic mode-locking,using a homodyne setup.We reveal that,after an abrupt perturbation,each soliton in the lattice undergoes damped oscillatory retiming within its trapping potential,while the retiming is strongly coupled to soliton dissipation.In addition,we show,through statistical analysis of the intra-cavity pulse spacing,how the trapping potentials are effective for suppressing timing jtter.The measurements and the theory developed in this work lay the groundwork for studies of the general stability and noise performance of harmonically mode-locked lasers as well as providing valuable insight into generic multi-pulse phenomena in mode-locked lasers.
基金supported by the National Natural Science Foundation of China(Nos.12435011,11905275,11775294,12122514,and 62205353)the Youth Innovation Promotion Association CAS,the National Postdoctoral Program for Innovative Talents(No.BX2021328)+1 种基金the China Postdoctoral Science Foundation(No.2021M703325)the CAS Project for Young Scientists in Basic Research(YSBR-115).
文摘An attosecond light source provides an advanced tool for investigating electron motion using time-resolvedspectroscopy techniques.Isolated attosecond pulses,especially,will significantlyadvance the study of electron dynamics.However,achieving high-intensity isolated attosecond pulses is still challenging at the present stage.In this paper,we propose a novel scheme for generating high-intensity,isolated attosecond soft x-ray free-electron lasers(FELs)using a mid-infrared(MiR)subcycle modulation laser from gas-filled hollow capillary fibers.The multi-cycle MlR pulses are first compressed to subcycles using a krypton-filled hollow capillary fiber with a decreasing pressure gradient due to the soliton self-compression effect.By utilizing such subcycle MlR laser pulses to modulate an electron beam,we can obtain a quasi-isolated current peak,which can then produce an isolated FEL pulse with a high signal-to-noise ratio,naturally synchronizing with the subcycle MiR laser pulse.Numerical simulations have been carried out,including subcycle pulse generation,electron beam modulation,and FEL radiation processes.The simulation results indicate that an isolated attosecond pulse with a wavelength of 1 nm,a peak power of~28 GW,a pulse duration of~580 as,and a signal-to-noise ratio of~96.2%can be generated by our proposed method.The numerical results demonstrated here pave a new way for generating a high-intensity isolated attosecond soft x-ray pulse,which may have many applications in nonlinear spectroscopy and atomic-site electronic processes.
基金supported by the National Key Research and Development Program of China(Nos.2024YFB3613502 and 2023YFB3307702)the Shanghai Pujiang Program(No.23PJ1414700)the National Natural Science Foundation of China(No.62435005)。
文摘We presented a repetition-rate tunable Yb-doped fiber laser system,which used a chirped fiber Bragg grating as a fiber stretcher designed to match the second-and third-order dispersion of the transmission grating compressor.The system delivered 1-μJ,143-fs pulses at a 2 MHz repetition rate and 10-μJ,157-fs pulses at a 200 kHz repetition rate,respectively.The pulse repetition rate can be tuned from 200 kHz to 2 MHz while the pulse duration maintains<180 fs.This compact fiber laser source was built for applications in ophthalmology,such as corneal flap cutting and tissue vaporization.Furthermore,it can be applied in micro-machining applications,such as laser marking,scribing,and drilling.
文摘Continuous-wave mode-locking at multi-GHz repetition rates is achieved in an ultrashort laser cavity at critical pulse energies 100 times lower than predicted by conventional theory.The authors reveal that dynamic gain depletion and recovery between consecutive round-trips is the key factor behind a low-pulse-energy transition from Q-switched mode-locking(QSML)to continuous-wave mode-locking(CWML).As well as providing new insight into gain dynamics,the results suggest a practical route to low-threshold lasing at very high-repetition rates.
基金supported by the National Natural Science Foundation of China(Grant Nos.62205353 and 62275254)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0650000)+1 种基金the Shanghai Science and Technology Plan Project Funding(Grant No.23JC1410100)the Fuyang High-level Talent Group Project
文摘We present the flexible delivery of picosecond laser pulses with up to 20 W average power over a 3-m-long sample of antiresonant hollow-core fiber(AR-HCF)for laser-micromachining applications.Our experiments highlight the importance of optical-mode purity of the AR-HCF for manufacturing precision.We demonstrate that compared with an AR-HCF sample with a capillary to core(d/D)ratio of approximately 0.5,the AR-HCF with a d/D ratio of approximately 0.68 exhibits better capability of high-order-mode suppression,giving rise to improved micromachining quality.Moreover,the AR-HCF delivery system exhibits better pointing stability and setup flexibility than the free-space beam delivery system.These results pave the way to practical applications of AR-HCF in developing advanced equipment for ultrafast laser micromachining.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘Mode-locked lasers have been widely used to explore interactions between optical solitons,including bound-soliton states that may be regarded as“photonic molecules”.Conventional mode-locked lasers normally,however,host at most only a few solitons,which means that stochastic behaviours involving large numbers of solitons cannot easily be studied under controlled experimental conditions.Here we report the use of an optoacoustically mode-locked fibre laser to create hundreds of temporal traps or“reactors”in parallel,within each of which multiple solitons can be isolated and controlled both globally and individually using all-optical methods.We achieve on-demand synthesis and dissociation of soliton molecules within these reactors,in this way unfolding a novel panorama of diverse dynamics in which the statistics of multi-soliton interactions can be studied.The results are of crucial importance in understanding dynamical soliton interactions and may motivate potential applications for all-optical control of ultrafast light fields in optical resonators.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.62250006,62072266,and 61836004the National Natural Science Foundation of China Youth Fund under Grant No.62202254,Beijing National Research Center for Information Science and Technology under Grant No.BNR2022RC01003+1 种基金the Tsinghua University Initiative Scientific Research Programthe Suzhou-Tsinghua Innovation Leadership Program.
文摘Brain-inspired computing is a new technology that draws on the principles of brain science and is oriented to the efficient development of artificial general intelligence(AGI),and a brain-inspired computing system is a hierarchical system composed of neuromorphic chips,basic software and hardware,and algorithms/applications that embody this tech-nology.While the system is developing rapidly,it faces various challenges and opportunities brought by interdisciplinary research,including the issue of software and hardware fragmentation.This paper analyzes the status quo of brain-inspired computing systems.Enlightened by some design principle and methodology of general-purpose computers,it is proposed to construct"general-purpose"brain-inspired computing systems.A general-purpose brain-inspired computing system refers to a brain-inspired computing hierarchy constructed based on the design philosophy of decoupling software and hardware,which can flexibly support various brain-inspired computing applications and neuromorphic chips with different architec-tures.Further,this paper introduces our recent work in these aspects,including the ANN(artificial neural network)/SNN(spiking neural network)development tools,the hardware agnostic compilation infrastructure,and the chip micro-archi-tecture with high flexibility of programming and high performance;these studies show that the"general-purpose"system can remarkably improve the efficiency of application development and enhance the productivity of basic software,thereby being conductive to accelerating the advancement of various brain-inspired algorithms and applications.We believe that this is the key to the collaborative research and development,and the evolution of applications,basic software and chips in this field,and conducive to building a favorable software/hardware ecosystem of brain-inspired computing.
