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Solitary beam propagation in periodic layered Kerr media enables high-efficiency pulse compression and mode self-cleaning

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Light(Science & Applications) 2021年第4期10卷 464-474页

作者： Sheng Zhang Zongyuan Fu Bingbing Zhu Guangyu Fan Yudong Chen Shunjia Wang Yaxin Liu Andrius Baltuska Cheng Jin Chuanshan Tian zhensheng tao State Key Laboratory of Surface Physics and Department of Physics Fudan UniversityShanghaiChina institute of Photonics TU WienGusshausstrasse 27/387ViennaAustria Department of Applied Physics Nanjing University of Science and TechnologyNanjingJiangsu 210094China

Generating intense ultrashort pulses with high-quality spatial modes is crucial for ultrafast and strong-field science and can be achieved by nonlinear supercontinuum generation(SCG)and pulse *** this work,we propose that the generation of quasi-stationary solitons in periodic layered Kerr media can greatly enhance the nonlinear lightmatter interaction and fundamentally improve the performance of SCG and pulse compression in condensed *** both experimental and theoretical studies,we successfully identify these solitary modes and reveal their unified condition for ***-time coupling is shown to strongly influence the stability of solitons,leading to variations in the spectral,spatial and temporal profiles of femtosecond *** advantage of the unique characteristics of these solitary modes,we first demonstrate single-stage SCG and the compression of femtosecond pulses from 170 to 22 fs with an efficiency>85%.The high spatiotemporal quality of the compressed pulses is further confirmed by highharmonic *** also provide evidence of efficient mode self-cleaning,which suggests rich spatiotemporal self-organization of the laser beams in a nonlinear resonator This work offers a route towards highly efficient,simple,stable and highly flexible SCG and pulse compression solutions for state-of-the-art ytterbium laser technology.

关键词： pulse resonator mode

探测凝聚态材料中电子的阿秒动力学以及相互作用过程(特邀)

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光子学报 2021年第8期50卷 62-76页

作者：陶镇生复旦大学物理学系表面物理国家重点实验室上海200438

随着高次谐波阿秒光源技术以及阿秒计量学的发展,对于凝聚态材料中的电子动力学探测也进入了阿秒的领域,并在近15年的时间里取得了显著的进展和突破。新颖的阿秒测量方式为研究在极短的时间尺度上,凝聚态材料中电子的运动、共振跃迁以... 详细信息

随着高次谐波阿秒光源技术以及阿秒计量学的发展,对于凝聚态材料中的电子动力学探测也进入了阿秒的领域,并在近15年的时间里取得了显著的进展和突破。新颖的阿秒测量方式为研究在极短的时间尺度上,凝聚态材料中电子的运动、共振跃迁以及相互作用等重要物理问题提供了全新的研究手段和重要创新机遇。本文介绍了探测凝聚态物质中本征阿秒动力学过程的重要工作,主要综述了高次谐波、阿秒脉冲测量、凝聚态材料阿秒光电子能谱探测的关键技术和现状。最后对阿秒光电子动力学测量技术的发展做出了展望。

关键词：超快光学阿秒脉冲高次谐波阿秒脉冲测量阿秒光电子能谱

Active spintronic-metasurface terahertz emitters with tunable chirality

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Advanced Photonics 2021年第5期3卷 52-61页

作者： Changqin Liu Shunjia Wang Sheng Zhang Qingnan Cai Peng Wang Chuanshan Tian Lei Zhou Yizheng Wu zhensheng tao Fudan University Department of Physics and State Key Laboratory of Surface PhysicsShanghaiChina Shanghai Research Center for Quantum Sciences ShanghaiChina

The ability to generate and manipulate broadband chiral terahertz waves is essential for applications in material imaging,terahertz sensing,and *** can also open up new possibilities for nonlinear terahertz spectroscopy and coherent control of chiral molecules and magnetic *** existing methods,however,often suffer from low efficiency,narrow bandwidth,or poor ***,we propose a novel type of laser-driven terahertz emitters,consisting of metasurface-patterned magnetic multilayer heterostructures,that can overcome the shortcomings of the conventional *** hybrid terahertz emitters combine the advantages of spintronic emitters for being ultrabroadband,efficient,and highly flexible,as well as those of metasurfaces for the powerful control capabilities over the polarization state of emitted terahertz waves on an ultracompact *** a stripe-patterned metasurface as an example,we demonstrate the efficient generation and manipulation of broadband chiral terahertz *** ellipticity can reach>0.75 over a broad terahertz bandwidth(1 to 5 THz),representing a high-quality and efficient source for few-cycle circularly polarized terahertz pulses with stable carrier *** control of ellipticity and helicity is also demonstrated with our systematic experiments and numerical *** show that the terahertz polarization state is dictated by the interplay between laser-induced spintronic-origin currents and the screening charges/currents in the metasurfaces,which exhibits tailored anisotropic properties due to the predesigned geometric confinement *** work opens a new pathway to metasurface-tailored spintronic emitters for efficient vector-control of electromagnetic waves in the terahertz regime.

关键词： chiral terahertz generation active metasurface time-domain terahertz spectroscopy

Nonrelativistic and nonmagnetic terahertz-wave generation via ultrafast current control in anisotropic conductive heterostructures

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Advanced Photonics 2023年第5期5卷 86-95页

作者： Sheng Zhang Yongwei Cui Shunjia Wang Haoran Chen Yaxin Liu Wentao Qin Tongyang Guan Chuanshan Tian Zhe Yuan Lei Zhou Yizheng Wu zhensheng tao Fudan University State Key Laboratory of Surface PhysicsDepartment of PhysicsShanghaiChina Fudan University Key Laboratory of Micro and Nano Photonic StructuresShanghaiChina Shanghai Research Center for Quantum Sciences ShanghaiChina Beijing Normal University Center for Advanced Quantum StudiesDepartment of PhysicsBeijingChina Fudan University Institute for Nanoelectronic Devices and Quantum ComputingShanghaiChina

Precise and ultrafast control over photo-induced charge currents across nanoscale interfaces could lead to important applications in energy harvesting,ultrafast electronics,and coherent terahertz *** studies have shown that several relativistic mechanisms,including inverse spin-Hall effect,inverse Rashba–Edelstein effect,and inverse spin-orbit-torque effect,can convert longitudinally injected spinpolarized currents from magnetic materials to transverse charge currents,thereby harnessing these currents for terahertz ***,these mechanisms typically require external magnetic fields and exhibit limitations in terms of spin-polarization rates and efficiencies of relativistic spin-to-charge *** present a nonrelativistic and nonmagnetic mechanism that directly utilizes the photoexcited high-density charge currents across the *** demonstrate that the electrical anisotropy of conductive oxides RuO2 and IrO2 can effectively deflect injected charge currents to the transverse direction,resulting in efficient and broadband terahertz ***,this mechanism has the potential to offer much higher conversion efficiency compared to previous methods,as conductive materials with large electrical anisotropy are readily available,whereas further increasing the spin-Hall angle of heavy-metal materials would be *** findings offer exciting possibilities for directly utilizing these photoexcited high-density currents across metallic interfaces for ultrafast electronics and terahertz spectroscopy.

关键词： terahertz optics ultrafast science nanophotonics

Localization of q-form fields on a de Sitter brane in chameleon gravity

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Frontiers of physics 2024年第3期19卷 11-18页

作者： Yi Zhong tao-tao Sui School of Physics and Electronics Science Hunan UniversityChangsha 410082China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China College of Physics Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Recently,it was found that the vector field can be naturally localized on the thick brane in chameleon *** this work,we extend this study to encompass de Sitter brane *** focus on the localization of q-form *** scalar and vector fields can be localized on the de Sitter brane,while the KR field cannot be *** condition for localization of the scalar and vector fields is ***,we investigate the localization characteristics in two examples with given conformal factor b(ϕ).In the first case,the effective potentials and KK modes of the matter fields are obtained asymmetric even though the de Sitter brane has Z2 *** the second case,volcano-like effective potentials are generated in the de Sitter brane model.

关键词： brane q-form field chameleon gravity

虹桥机场T1航站楼局部区域大面积失电与谐波的关系及应对措施

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现代建筑电气 2017年第8期8卷 43-48页

作者：陶震胜上海机场建设指挥部上海201202

针对虹桥机场T1航站楼改造工程第一阶段A楼试运行阶段发生的多次局部大面积失电现象,通过排查及数据检测来分析局部大面积失电事故与谐波之间的关系,确定临时应对措施及长期解决方案,以提高航站楼供电系统安全性、可靠性。

关键词：大面积失电谐波剩余电流动作保护器 UPS供电系统

Phase-Matched High-Harmonic Generation under Nonadiabatic Conditions:Model and Experiment

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Ultrafast Science 2023年第6期3卷 69-77页

作者： Yudong Chen Zongyuan Fu Baochang Li Sainan Peng Bingbing Zhu Guangyu Fan Yi Liu Chengyuan Ding Cheng Jin zhensheng tao State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano Photonic Structures(MOE)and Department of PhysicsFudan UniversityShanghai 200433China Department of Applied Physics Nanjng University of Science and TechnologyNanjingJiangsu 210094China Shanghai Key Lab of Modern Optical System University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghaiChina MIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Nanjing University of Science and TechnologyNanjingJiangsu 210094China

Nonadiabatic phase matching of high-harmonic generation(HHG)driven by few-cycle laser pulses is essential for extending harmonic energy and generating isolated attosecond ***,understanding nonadiabatic HHG is challenging due to the complex interplay of various optical phases driven by temporally and spatially varying laser *** calculations typically rely on computationally demanding 3-dimensional simulations,which can make it difficult to extract the essential features of nonadiabatic *** this work,we develop a computationally efficient 2-dimensional model that directly considers various phase contributions of *** model can well explain the experimentally observed pressure-and intensity-dependent behaviors of different harmonic *** appropriately parameterizing the single-atom response,our model can also estimate the variation of HHG spectra under different driving *** model can provide an efficient tool for the design and optimization of HHG-based applications.

关键词： harmonic adiabatic generating

A Global Optimality Principle for Fully Coupled Mean-field Control Systems

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 379-413页

作者： tao HAO School of Statistics and Mathematics Shandong University of Finance and EconomicsJinan 250014China

This paper concerns a global optimality principle for fully coupled mean-field control *** the first-order and the second-order variational equations are fully coupled mean-field linear FBSDEs. A new linear relation is introduced, with which we successfully decouple the fully coupled first-order variational equations. We give a new second-order expansion of Y^(ε) that can work well in mean-field framework. Based on this result, the stochastic maximum principle is proved. The comparison with the stochastic maximum principle for controlled mean-field stochastic differential equations is supplied.

关键词： optimal control global maximum principle fully coupled general mean-field FBSDE adjoint equation recursive utility

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资源禀赋、结构差异与农产品贸易

中国农村经济 2019年第4期 111-129页

作者：乔长涛付宏陶珍生汪金伟湖北经济学院经济与贸易学院中国社会科学院人口与劳动经济研究所中国社会科学院工业经济研究所

本文在新古典资源禀赋理论框架下,以Bergstrand广义引力模型为基础引入社会网络分析工具,利用UN-Comtrade和CEPII 2007～2016年SITC-4位数中国农产品进出口贸易数据,借助泊松家族准极大似然估计法,考察了二元层面资源禀赋差异与体系层... 详细信息

本文在新古典资源禀赋理论框架下,以Bergstrand广义引力模型为基础引入社会网络分析工具,利用UN-Comtrade和CEPII 2007～2016年SITC-4位数中国农产品进出口贸易数据,借助泊松家族准极大似然估计法,考察了二元层面资源禀赋差异与体系层面结构差异对农产品贸易的影响及其作用机理。研究发现,除传统二元层面资源禀赋差异外,来自体系层面的结构差异通过替代效应和分层效应对农产品贸易产生了显著影响:结构对等性的存在削弱了农产品贸易对传统资源禀赋的依赖;角色对等性解释了资源禀赋差异对贸易核心国和非核心国的影响存在显著差异。具体而言,与结构相似性水平高的国家开展农产品贸易能在相当程度上缓解资本和土地等资源禀赋的约束作用;与处于世界体系不同位置上的国家开展农产品贸易,资本禀赋差异对非核心贸易伙伴国的农产品贸易的抑制作用显著大于核心国,而土地禀赋差异的影响则相反,对核心国的影响大于非核心国。

关键词：资源禀赋结构因素替代效应分层效应