We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Sch...We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Schr?dinger equation.It is demonstrated that the atomic photoelectron spectra oscillate out of step as a function of electron kinetic energies for different initial states(2s or 2_(p0)),which is well reproduced by the simulations based on strong field approximation,and the above distinct feature is ascribed to the different interferences from the partial electron wave packets detached by positive and negative electric fields for different initial states of 2s and 2_(p0).展开更多
We derive the transport equations from the Vlasov–Fokker–Planck equation when the velocity space is spherically symmetric.The Shkarofsky's form of Fokker–Planck–Rosenbluth collision operator is employed in the...We derive the transport equations from the Vlasov–Fokker–Planck equation when the velocity space is spherically symmetric.The Shkarofsky's form of Fokker–Planck–Rosenbluth collision operator is employed in the Vlasov–Fokker–Planck equation.A closed-form relaxation model for homogeneous plasmas could be presented in terms of Gauss hypergeometric2F1functions.This has been accomplished based on the Maxwellian mixture model.Furthermore,we demonstrate that classic models such as two-temperature thermal equilibrium model and thermodynamic equilibrium model are special cases of our relaxation model and the zeroth-order Braginskii heat transfer model can also be derived.The present relaxation model is a nonequilibrium model based on the hypothesis that the plasmas system possesses finitely distinguishable independent features,without relying on the conventional near-equilibrium assumption.展开更多
Edge structures are ubiquitous in the processing and fabrication of various optoelectronic devices.Novel physical properties and enhanced light–matter interactions are anticipated to occur at crystal edges due to the...Edge structures are ubiquitous in the processing and fabrication of various optoelectronic devices.Novel physical properties and enhanced light–matter interactions are anticipated to occur at crystal edges due to the broken spatial translational symmetry.However,the intensity of first-order Raman scattering at crystal edges has been rarely explored,although the mechanical stress and edge characteristics have been thoroughly studied by the Raman peak shift and the spectral features of the edge-related Raman modes.Here,by taking Ga As crystal with a well-defined edge as an example,we reveal the intensity enhancement of Raman-active modes and the emergence of Raman-forbidden modes under specific polarization configurations at the edge.This is attributed to the presence of a hot spot at the edge due to the redistributed electromagnetic fields and electromagnetic wave propagations of incident laser and Raman signal near the edge,which are confirmed by the finite-difference time-domain simulations.Spatially-resolved Raman intensities of both Raman-active and Raman-forbidden modes near the edge are calculated based on the redistributed electromagnetic fields,which quantitatively reproduce the corresponding experimental results.These findings offer new insights into the intensity enhancement of Raman scattering at crystal edges and present a new avenue to manipulate light–matter interactions of crystal by manufacturing various types of edges and to characterize the edge structures in photonic and optoelectronic devices.展开更多
本文设计了由不对称半圆柱对阵列组成的全介质超构表面,获得了两个高品质因子的准连续域束缚态模式(quasi-bound states in the continuum,QBIC).通过选择不同形式的对称破缺,在近红外频段均可产生两个稳健的QBIC,并且二者的谐振波长、...本文设计了由不对称半圆柱对阵列组成的全介质超构表面,获得了两个高品质因子的准连续域束缚态模式(quasi-bound states in the continuum,QBIC).通过选择不同形式的对称破缺,在近红外频段均可产生两个稳健的QBIC,并且二者的谐振波长、品质因子、偏振依赖等表现出不同的特性.模拟计算表明,通过测量两个QBIC的谐振波长,能够实现折射率和温度的双参数传感;通过调节不对称参数,利用QBIC的品质因子依赖于不对称参数的二次方反比关系,理论上能够提高品质因子到任意的数值,从而实现传感性能的提升和调节.该超构表面的折射率传感灵敏度、品质因子和优值分别达到194.7 nm/RIU,45829和8197,其温度传感灵敏度达到24 pm/℃.展开更多
基金Project supported by Li Ka Shing Foundation STUGTIIT Joint Research(Grant No.2024LKSFG02)the STU Scientific Research Foundation for Talents(Grant Nos.NTF22026,NTF23011,NTF23014,and NTF23036T)+1 种基金the National Basic Research Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.12074239 and 12274300)。
文摘We have performed a comparative study of the photoelectron spectra adopting different initial states(2s or 2_(p0))of hydrogen atoms in a near-infrared laser pulse by using the full three-dimensional time-dependent Schr?dinger equation.It is demonstrated that the atomic photoelectron spectra oscillate out of step as a function of electron kinetic energies for different initial states(2s or 2_(p0)),which is well reproduced by the simulations based on strong field approximation,and the above distinct feature is ascribed to the different interferences from the partial electron wave packets detached by positive and negative electric fields for different initial states of 2s and 2_(p0).
基金Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0500302 and LSKJ202300305)。
文摘We derive the transport equations from the Vlasov–Fokker–Planck equation when the velocity space is spherically symmetric.The Shkarofsky's form of Fokker–Planck–Rosenbluth collision operator is employed in the Vlasov–Fokker–Planck equation.A closed-form relaxation model for homogeneous plasmas could be presented in terms of Gauss hypergeometric2F1functions.This has been accomplished based on the Maxwellian mixture model.Furthermore,we demonstrate that classic models such as two-temperature thermal equilibrium model and thermodynamic equilibrium model are special cases of our relaxation model and the zeroth-order Braginskii heat transfer model can also be derived.The present relaxation model is a nonequilibrium model based on the hypothesis that the plasmas system possesses finitely distinguishable independent features,without relying on the conventional near-equilibrium assumption.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFA1407000)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB0460000)+4 种基金the National Natural Science Foundation of China(Grant Nos.12322401,12127807,and 12393832)CAS Key Research Program of Frontier Sciences(Grant No.ZDBS-LY-SLH004)Beijing Nova Program(Grant No.20230484301)Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2023125)CAS Project for Young Scientists in Basic Research(Grant No.YSBR-026)。
文摘Edge structures are ubiquitous in the processing and fabrication of various optoelectronic devices.Novel physical properties and enhanced light–matter interactions are anticipated to occur at crystal edges due to the broken spatial translational symmetry.However,the intensity of first-order Raman scattering at crystal edges has been rarely explored,although the mechanical stress and edge characteristics have been thoroughly studied by the Raman peak shift and the spectral features of the edge-related Raman modes.Here,by taking Ga As crystal with a well-defined edge as an example,we reveal the intensity enhancement of Raman-active modes and the emergence of Raman-forbidden modes under specific polarization configurations at the edge.This is attributed to the presence of a hot spot at the edge due to the redistributed electromagnetic fields and electromagnetic wave propagations of incident laser and Raman signal near the edge,which are confirmed by the finite-difference time-domain simulations.Spatially-resolved Raman intensities of both Raman-active and Raman-forbidden modes near the edge are calculated based on the redistributed electromagnetic fields,which quantitatively reproduce the corresponding experimental results.These findings offer new insights into the intensity enhancement of Raman scattering at crystal edges and present a new avenue to manipulate light–matter interactions of crystal by manufacturing various types of edges and to characterize the edge structures in photonic and optoelectronic devices.
文摘本文设计了由不对称半圆柱对阵列组成的全介质超构表面,获得了两个高品质因子的准连续域束缚态模式(quasi-bound states in the continuum,QBIC).通过选择不同形式的对称破缺,在近红外频段均可产生两个稳健的QBIC,并且二者的谐振波长、品质因子、偏振依赖等表现出不同的特性.模拟计算表明,通过测量两个QBIC的谐振波长,能够实现折射率和温度的双参数传感;通过调节不对称参数,利用QBIC的品质因子依赖于不对称参数的二次方反比关系,理论上能够提高品质因子到任意的数值,从而实现传感性能的提升和调节.该超构表面的折射率传感灵敏度、品质因子和优值分别达到194.7 nm/RIU,45829和8197,其温度传感灵敏度达到24 pm/℃.
