The ultrafast laser-matter interaction is explored to induce new pioneering principles and technologies into the realms of fundamental science and industrial production.The local thermal melting and connection propert...The ultrafast laser-matter interaction is explored to induce new pioneering principles and technologies into the realms of fundamental science and industrial production.The local thermal melting and connection properties of the ultrafast laser welding technology offer a novel method for welding of diverse transparent materials,thus having wide range of potential applications in aerospace,opto-mechanical systems,sensors,microfluidic,optics,etc.In this comprehensive review,tuning the transient electron activation processes,high-rate laser energy deposition,and dynamic evolution of plasma morphology by the temporal/spatial shaping methods have been demonstrated to facilitate the transition from conventional homogeneous transparent material welding to the more intricate realm of transparent/metal heterogeneous material welding.The welding strength and stability are also improvable through the implementation of real-time,in-situ monitoring techniques and the prompt diagnosis of welding defects.The principles of ultrafast laser welding,bottleneck problems in the welding,novel welding methods,advances in welding performance,in-situ monitoring and diagnosis,and various applications are reviewed.Finally,we offer a forward-looking perspective on the fundamental challenges within the field of ultrafast laser welding and identify key areas for future research,underscoring the imperative need for ongoing innovation and exploration.展开更多
Bursts of GHz repetition rate pulses involve more ablation mechanisms than single femtosecond pulses.Efficient ablation by GHz laser pulses is a multi-step process,consisting of a first thermal incubation phase,follow...Bursts of GHz repetition rate pulses involve more ablation mechanisms than single femtosecond pulses.Efficient ablation by GHz laser pulses is a multi-step process,consisting of a first thermal incubation phase,followed by a highly efficient ablation phase.GHz ablation therefore combines thermal and non-thermal ablation mechanisms.With an optimal choice of the burst duration,the ablation efficiency can be highly enhanced.Long bursts,comprising tens of pulses to hundreds of pulses,are needed to take full advantage of the increase in ablation efficiency.展开更多
We designed a femtosecond(fs)+picosecond(ps)double-pulse sequence by using a Mach-Zehnder-like apparatus to split a single 120 fs pulse into two sub-pulses,and one of them was stretched to a width of 2 ps by a four-pa...We designed a femtosecond(fs)+picosecond(ps)double-pulse sequence by using a Mach-Zehnder-like apparatus to split a single 120 fs pulse into two sub-pulses,and one of them was stretched to a width of 2 ps by a four-pass grating system.Through observing the ripples induced on the ZnO surface,we found the ionization rate appeared to be higher for the sequence in which the fs pulse arrived first.The electron rate equation was used to calculate changes of electron density distribution for the sequences with different delay times.We suggest that using a temporally shaped fs+ps pulse sequence can achieve nonlinear ionization control and influence the induced ripples.展开更多
Deterministically achieving on-chip photon storage and retrieval is a fundamental challenge for integrated photonics.Moreover,this requirement is increasingly urgent as photon storage and retrieval is crucial to reali...Deterministically achieving on-chip photon storage and retrieval is a fundamental challenge for integrated photonics.Moreover,this requirement is increasingly urgent as photon storage and retrieval is crucial to realize truly scalable room-temperature quantum computing.However,most of existing quantum memories integrated on chips must either work at cryogenic temperature or else are strongly coupled with the environment,which hugely reduces the efficiency.Here,we propose an on-chip room-temperature quantum memory comprising three coupled microcavities,which presents an ideal dark state decoupled by a waveguide,thereby allowing on-demand photon storage and retrieval with high efficiency and high fidelity simultaneously.Furthermore,we demonstrate that the single-photon temporal duration can be increased or decreased by a factor of 10^(3),thereby enabling many crucial quantum applications.Our error-robust approach highlights the potential for a solid-state photonic molecule for use as on-chip quantum memory and for optical quantum computing.展开更多
This paper reviews recent progresses on optical arbitrary waveform generation （AWG） techniques, which could be used to break the speed and bandwidth bottle- necks of electronics technologies for waveform generation....This paper reviews recent progresses on optical arbitrary waveform generation （AWG） techniques, which could be used to break the speed and bandwidth bottle- necks of electronics technologies for waveform generation. The main enabling techniques for optically generating optical and microwave waveforms are introduced and reviewed in this paper, such as wavelength-to-time mapping techniques, space-to-time mapping techniques, temporal pulse shaping （TPS） system, optoelectronics oscillator （OEO）, programmable optical filters, optical differentiator and integrator and versatile electro-optic modulation implementations. The main advantages and challenges of these optical AWG techniques are also discussed.展开更多
This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgr...This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgrade to the original LCLS at SLAC National Accelerator Laboratory.This advanced laser system generates high-quality laser beams for the LCLS-II,contributing to the instrument's unprecedented brightness,precision and flexibility.Our discussion extends to the various subsystems that comprise the photoinjector,including the photocathode laser,laser heater and beam transport systems.Lastly,we draw attention to the ongoing research and development infrastructure underway to enhance the functionality and efficiency of the LCLS-II,and similar X-ray free-electron laser facilities around the world,thereby contributing to the future of laser technology and its applications.展开更多
基金supports from National Key R&D Program of China(Grant No.2023YFB4605500)National Natural Science Foundation of China(Grant No.52105498)+3 种基金Natural Science Foundation of Hunan Province(Grant No.2022JJ40597)the Science and Technology Innovation Program of Hunan Province(Grant No.2022RC1132)State Key Laboratory of Precision Manufacturing for Extreme Service Performance(Grant No.ZZYJKT2023-08)support in analyzing the status of ultrafast laser welding applications,as well as the corresponding project support(Grant No.HKF202400595).
文摘The ultrafast laser-matter interaction is explored to induce new pioneering principles and technologies into the realms of fundamental science and industrial production.The local thermal melting and connection properties of the ultrafast laser welding technology offer a novel method for welding of diverse transparent materials,thus having wide range of potential applications in aerospace,opto-mechanical systems,sensors,microfluidic,optics,etc.In this comprehensive review,tuning the transient electron activation processes,high-rate laser energy deposition,and dynamic evolution of plasma morphology by the temporal/spatial shaping methods have been demonstrated to facilitate the transition from conventional homogeneous transparent material welding to the more intricate realm of transparent/metal heterogeneous material welding.The welding strength and stability are also improvable through the implementation of real-time,in-situ monitoring techniques and the prompt diagnosis of welding defects.The principles of ultrafast laser welding,bottleneck problems in the welding,novel welding methods,advances in welding performance,in-situ monitoring and diagnosis,and various applications are reviewed.Finally,we offer a forward-looking perspective on the fundamental challenges within the field of ultrafast laser welding and identify key areas for future research,underscoring the imperative need for ongoing innovation and exploration.
文摘Bursts of GHz repetition rate pulses involve more ablation mechanisms than single femtosecond pulses.Efficient ablation by GHz laser pulses is a multi-step process,consisting of a first thermal incubation phase,followed by a highly efficient ablation phase.GHz ablation therefore combines thermal and non-thermal ablation mechanisms.With an optimal choice of the burst duration,the ablation efficiency can be highly enhanced.Long bursts,comprising tens of pulses to hundreds of pulses,are needed to take full advantage of the increase in ablation efficiency.
基金financially supported by the National Natural Science Foundation of China(Nos.12274280,11774220 and 11974147)。
文摘We designed a femtosecond(fs)+picosecond(ps)double-pulse sequence by using a Mach-Zehnder-like apparatus to split a single 120 fs pulse into two sub-pulses,and one of them was stretched to a width of 2 ps by a four-pass grating system.Through observing the ripples induced on the ZnO surface,we found the ionization rate appeared to be higher for the sequence in which the fs pulse arrived first.The electron rate equation was used to calculate changes of electron density distribution for the sequences with different delay times.We suggest that using a temporally shaped fs+ps pulse sequence can achieve nonlinear ionization control and influence the induced ripples.
文摘Deterministically achieving on-chip photon storage and retrieval is a fundamental challenge for integrated photonics.Moreover,this requirement is increasingly urgent as photon storage and retrieval is crucial to realize truly scalable room-temperature quantum computing.However,most of existing quantum memories integrated on chips must either work at cryogenic temperature or else are strongly coupled with the environment,which hugely reduces the efficiency.Here,we propose an on-chip room-temperature quantum memory comprising three coupled microcavities,which presents an ideal dark state decoupled by a waveguide,thereby allowing on-demand photon storage and retrieval with high efficiency and high fidelity simultaneously.Furthermore,we demonstrate that the single-photon temporal duration can be increased or decreased by a factor of 10^(3),thereby enabling many crucial quantum applications.Our error-robust approach highlights the potential for a solid-state photonic molecule for use as on-chip quantum memory and for optical quantum computing.
基金Acknowledgements We would like to thank our colleagues for their contributions in these works, such as Reza Ashrafi, Chao Wang, Tae-Jung Ahn, Ze Li, Wei Li, Ningbo Huang, Ye Deng, Yi Hu, Roberto Morandotti, Yichen Han, Shilong Pan, Maria Rosario and Wangzhe Li. This work was supported by the National Natural Science Foundation of China （Grant Nos. 61377002, 61321063, and 61090391）. This work was also supported by the Natural Sciences and Engineering Research Council of Canada （NSERC）. Ming Li was supported in part by the ＂Thousand Young Talent＂ program.
文摘This paper reviews recent progresses on optical arbitrary waveform generation （AWG） techniques, which could be used to break the speed and bandwidth bottle- necks of electronics technologies for waveform generation. The main enabling techniques for optically generating optical and microwave waveforms are introduced and reviewed in this paper, such as wavelength-to-time mapping techniques, space-to-time mapping techniques, temporal pulse shaping （TPS） system, optoelectronics oscillator （OEO）, programmable optical filters, optical differentiator and integrator and versatile electro-optic modulation implementations. The main advantages and challenges of these optical AWG techniques are also discussed.
基金the support from the SLAC National Accelerator Laboratory,the U.S.Department of Energy(DOE),the Office of Science,Office of Basic Energy Sciences under Contract No.DE-AC02-76SF00515,No.DE-SC0022559,No.DE-SC0022464,No.DE-FOA0002859the National Science Foundation under Contract No.2231334the U.S.Department of Defense under a National Defense Science and Engineering Fellowship。
文摘This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgrade to the original LCLS at SLAC National Accelerator Laboratory.This advanced laser system generates high-quality laser beams for the LCLS-II,contributing to the instrument's unprecedented brightness,precision and flexibility.Our discussion extends to the various subsystems that comprise the photoinjector,including the photocathode laser,laser heater and beam transport systems.Lastly,we draw attention to the ongoing research and development infrastructure underway to enhance the functionality and efficiency of the LCLS-II,and similar X-ray free-electron laser facilities around the world,thereby contributing to the future of laser technology and its applications.
