The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was...The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was enhanced in both pump-induced and probe-induced processes,suggesting an extraordinary resonance absorption of photon-phonon coupling(PPC)with intrinsic anisotropic characteristic in carrier relaxation,regardless of the concrete crystallinity and orientation of GaAs sample.The results,delivering in-depth cognition about the polarization-dependent ultrafast carrier dynamics,also proved the paramount importance of interaction between polarized laser and semiconductor.展开更多
A novel broadband directional coupler based on an asymmetric dual-core photonic crystal fibet(PCF)is proposed.The asymmetry in the fiher is introduced by the enlargement of one air-hole in dual-core PCF.Numerical inve...A novel broadband directional coupler based on an asymmetric dual-core photonic crystal fibet(PCF)is proposed.The asymmetry in the fiher is introduced by the enlargement of one air-hole in dual-core PCF.Numerical investigation demonstrate that broadband directional coupling with spectral width as large as 370 nm and polarization-dependent loss and uniformity lower than 0.2 and 0.5 dB,respectively,can be achieved.In addition,the proposed fiber shows large tolerance to the variation of the fiber parameters.In particular,the fiber length allows at least 10%derivation from the proposed fiber length of 7.7 mm.展开更多
As a natural biaxial hyperbolic material, α-phase molybdenum trioxide(α-MoO_(3)) exhibits dielectric and metallic properties in the plane, rendering it an exceptional candidate for polarization-dependent devices. In...As a natural biaxial hyperbolic material, α-phase molybdenum trioxide(α-MoO_(3)) exhibits dielectric and metallic properties in the plane, rendering it an exceptional candidate for polarization-dependent devices. In this work, we design a lithography-free polarization-dependent absorber consisting of an α-MoO_(3)film, a germanium layer, and a silver substrate. The results show that a narrowband absorption of up to 0.99 is achieved at a wavelength of 12.2 μm for transverse magnetic polarization. In contrast, the absorption is only 0.06 at this wavelength for transverse electric polarization. This remarkable polarization-dependent absorption performance is attributed to the coupling of epsilon-near-zero modes and Fabry-Perot resonances, which is confirmed by the electric field and power dissipation density distributions. Furthermore, strong polarization-dependent performance could also be achieved when the crystal axis of α-MoO_(3)is rotated in the out-of-plane. This work demonstrates that in-plane anisotropic α-MoO_(3)has the potential for designing high polarization-dependent devices.展开更多
Active control of metamaterial properties with high tunability of both resonant intensity and frequency is essential for advanced terahertz(THz) applications, ranging from spectroscopy and sensing to communications.Am...Active control of metamaterial properties with high tunability of both resonant intensity and frequency is essential for advanced terahertz(THz) applications, ranging from spectroscopy and sensing to communications.Among varied metamaterials, plasmon-induced transparency(PIT) has enabled active control with giant sensitivity by embedding semiconducting materials. However, there is still a stringent challenge to achieve dynamic responses in both intensity and frequency modulation. Here, an anisotropic THz active metamaterial device with an ultrasensitive modulation feature is proposed and experimentally studied. A radiative-radiative-coupled PIT system is established, with a frequency shift of 0.26 THz in its sharp transparent windows by polarization rotation. Enabled by high charge-carrier mobility and longer diffusion lengths, we utilize a straightforwardly spincoated MAPbI3 film acting as a photoactive medium to endow the device with high sensitivity and ultrafast speed.When the device is pumped by an ultralow laser fluence, the PIT transmission windows at 0.86 and 1.12 THz demonstrate a significant reduction for two polarizations, respectively, with a full recovery time of 561 ps. In addition, we numerically prove the validity that the investigated resonator structure is sensitive to the optically induced conductivity. The hybrid system not only achieves resonant intensity and frequency modulations simultaneously, but also preserves the all-optical-induced switching merits with high sensitivity and speed, which enriches multifunctional subwavelength metamaterial devices at THz frequencies.展开更多
Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extract...Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase.The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.展开更多
Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here,...Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS2 monolayer with Ag nanowire （NW） and nanoparticle （NP） structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G （R6G） molecules can be achieved at ＂hotspots＂ formed in the Ag NW-Ag NP-MoS2 hybrid structure, with an enhancement factor of 106. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10-11 M, as well as reliable reproducibility and good stability.展开更多
This paper investigates the stereodynamics of the reaction He＋HD^＋ by the quasi-classical trajectory （QCT） method using the most accurate AQUILANTI surface [Aquilanti et al 2000 Mol. Phys. 98 1835]. The distributi...This paper investigates the stereodynamics of the reaction He＋HD^＋ by the quasi-classical trajectory （QCT） method using the most accurate AQUILANTI surface [Aquilanti et al 2000 Mol. Phys. 98 1835]. The distribution P（Фτ） of dihedral angle and the distribution P（θτ） of angle between k and j＇ have been presented at three different collision energies. Four generalized polarization-dependent differential cross-sections （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22/dωt）, （（2π/σ）（dσ21-/dωt） are also calculated. Some interesting results are obtained from the comparison of the stereodynamics of the title reaction at different collision energies.展开更多
This paper studies the influence of the reagent vibration on the reaction O（1D）＋HF→HO＋F by using a quasiclassical trajectory method on the new ab initio 1A＇ ground singlet potential energy surface （Gomez-Carras...This paper studies the influence of the reagent vibration on the reaction O（1D）＋HF→HO＋F by using a quasiclassical trajectory method on the new ab initio 1A＇ ground singlet potential energy surface （Gomez-Carrasco et al 2007 Chem. Phys. Lett. 435 188 193）. The product angular distributions which reflect the vector correlation are calculated. Four polarization-dependent differential cross sections （PDDCSs） which are sensitive to many photoinitiated bimolecular reaction experiments are presented in the center of the mass frame, respectively. The differential cross section indicates that the OH product mainly tends to the forward scattering, and other PDDCSs are also influenced by the vibration levels of HF.展开更多
The product polarizations of the title reactions are investigated by employing the quasi-classical trajectory （QCT） method. The four generalized polarization-dependent differential cross-sections （PDDCSs） （2π/...The product polarizations of the title reactions are investigated by employing the quasi-classical trajectory （QCT） method. The four generalized polarization-dependent differential cross-sections （PDDCSs） （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22＋/dωt）, and （2π/σ）（dσ21-/dωt） are calculated in the centre-of-mass frame. The distribution of the angle between κ and j＇, P（θr）, the distribution of the dihedral angle denoting κ-κ＇-j＇ correlation, P（Фr）, as well as the angular distribution of product rotational vectors in the form of polar plots P（θr, Фr） are calculated. The isotope effect is also revealed and primarily attributed to the difference in mass factor between the two title reactions.展开更多
Quasiclassical trajectory calculation of the title reaction O（^3P）＋H2→OH＋H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A＂ has been done. D...Quasiclassical trajectory calculation of the title reaction O（^3P）＋H2→OH＋H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A＂ has been done. Distribution P（θr） of polar angles between the relative velocityk of the reactant and rotational angular momentum vector j＇ of the product, distribution P（φr） of the azimuthal as well as dihedral angles correlating k-k＇-j＇, 3-dimensional distri-bution, and polarization-dependent differential cross sections （PDDCSs）dependent upon the scattering angle of the product molecule OH between the relative velocity k of the reactant and k＇ of the product at different scattering energies of 0.5, 0.75, and 1.0 eV are presented and discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51875006 and 51705009)。
文摘The transient dynamics of anisotropic properties of Ga As was systematically studied by polarization-dependent ultrafast time-resolved transient absorption.Our findings revealed that the anisotropy of reflectivity was enhanced in both pump-induced and probe-induced processes,suggesting an extraordinary resonance absorption of photon-phonon coupling(PPC)with intrinsic anisotropic characteristic in carrier relaxation,regardless of the concrete crystallinity and orientation of GaAs sample.The results,delivering in-depth cognition about the polarization-dependent ultrafast carrier dynamics,also proved the paramount importance of interaction between polarized laser and semiconductor.
基金supported by the Senior Talent Foundation of Jiangsu University(06JDG062)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(08KJB510001)+2 种基金Qianjiang Talent Project of Zhejiang Province(2007R10015)the Science Foundation of Ningbo(2008A610001)the National Natural Science Foundation of China(10574058 and 50735001)
文摘A novel broadband directional coupler based on an asymmetric dual-core photonic crystal fibet(PCF)is proposed.The asymmetry in the fiher is introduced by the enlargement of one air-hole in dual-core PCF.Numerical investigation demonstrate that broadband directional coupling with spectral width as large as 370 nm and polarization-dependent loss and uniformity lower than 0.2 and 0.5 dB,respectively,can be achieved.In addition,the proposed fiber shows large tolerance to the variation of the fiber parameters.In particular,the fiber length allows at least 10%derivation from the proposed fiber length of 7.7 mm.
基金supported by the National Natural Science Foundation of China (Grant No. 52106099)Shandong Provincial Natural Science Foundation (Grant No. ZR2022YQ57)+1 种基金Taishan Scholars ProgramBasic and Applied Basic Research Fund Project of Guangdong Province (Grant No. 2019A1515111178)。
文摘As a natural biaxial hyperbolic material, α-phase molybdenum trioxide(α-MoO_(3)) exhibits dielectric and metallic properties in the plane, rendering it an exceptional candidate for polarization-dependent devices. In this work, we design a lithography-free polarization-dependent absorber consisting of an α-MoO_(3)film, a germanium layer, and a silver substrate. The results show that a narrowband absorption of up to 0.99 is achieved at a wavelength of 12.2 μm for transverse magnetic polarization. In contrast, the absorption is only 0.06 at this wavelength for transverse electric polarization. This remarkable polarization-dependent absorption performance is attributed to the coupling of epsilon-near-zero modes and Fabry-Perot resonances, which is confirmed by the electric field and power dissipation density distributions. Furthermore, strong polarization-dependent performance could also be achieved when the crystal axis of α-MoO_(3)is rotated in the out-of-plane. This work demonstrates that in-plane anisotropic α-MoO_(3)has the potential for designing high polarization-dependent devices.
基金National Natural Science Foundation of China(NSFC)(11802339,11804387,11805276,61801498,61805282)Scientific Researches Foundation of National University of Defense Technology(ZK16-03-59,ZK18-01-03,ZK18-03-22,ZK18-03-36)+4 种基金Natural Science Foundation of Hunan Province(2016JJ1021)Open Director Fund of State Key Laboratory of Pulsed Power Laser Technology(SKL2018ZR05)Open Research Fund of Hunan Provincial Key Laboratory of High Energy Technology(GNJGJS03)Opening Foundation of State Key Laboratory of Laser Interaction with Matter(SKLLIM1702)Youth Talent Lifting Project(17-JCJQ-QT-004)
文摘Active control of metamaterial properties with high tunability of both resonant intensity and frequency is essential for advanced terahertz(THz) applications, ranging from spectroscopy and sensing to communications.Among varied metamaterials, plasmon-induced transparency(PIT) has enabled active control with giant sensitivity by embedding semiconducting materials. However, there is still a stringent challenge to achieve dynamic responses in both intensity and frequency modulation. Here, an anisotropic THz active metamaterial device with an ultrasensitive modulation feature is proposed and experimentally studied. A radiative-radiative-coupled PIT system is established, with a frequency shift of 0.26 THz in its sharp transparent windows by polarization rotation. Enabled by high charge-carrier mobility and longer diffusion lengths, we utilize a straightforwardly spincoated MAPbI3 film acting as a photoactive medium to endow the device with high sensitivity and ultrafast speed.When the device is pumped by an ultralow laser fluence, the PIT transmission windows at 0.86 and 1.12 THz demonstrate a significant reduction for two polarizations, respectively, with a full recovery time of 561 ps. In addition, we numerically prove the validity that the investigated resonator structure is sensitive to the optically induced conductivity. The hybrid system not only achieves resonant intensity and frequency modulations simultaneously, but also preserves the all-optical-induced switching merits with high sensitivity and speed, which enriches multifunctional subwavelength metamaterial devices at THz frequencies.
文摘Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase.The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.
基金This work was supported by the National Natural Science Foundation of China （No. 11274,395）, the Program for Changjiang Scholars and Innovative Research Team in University （No. IRT13042） and the Open Fund of the Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications （Jinan University）.
文摘Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS2 monolayer with Ag nanowire （NW） and nanoparticle （NP） structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G （R6G） molecules can be achieved at ＂hotspots＂ formed in the Ag NW-Ag NP-MoS2 hybrid structure, with an enhancement factor of 106. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10-11 M, as well as reliable reproducibility and good stability.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10504017 and 10474060)the Key Project of Chinese Ministry of Education (Grant No 206093)
文摘This paper investigates the stereodynamics of the reaction He＋HD^＋ by the quasi-classical trajectory （QCT） method using the most accurate AQUILANTI surface [Aquilanti et al 2000 Mol. Phys. 98 1835]. The distribution P（Фτ） of dihedral angle and the distribution P（θτ） of angle between k and j＇ have been presented at three different collision energies. Four generalized polarization-dependent differential cross-sections （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22/dωt）, （（2π/σ）（dσ21-/dωt） are also calculated. Some interesting results are obtained from the comparison of the stereodynamics of the title reaction at different collision energies.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574083)the Natural Science Foundation of Shandong Province of China (Grant No Y2006A23)partially by the National Basic Research Program of China (GrantNo 2006CB806000)
文摘This paper studies the influence of the reagent vibration on the reaction O（1D）＋HF→HO＋F by using a quasiclassical trajectory method on the new ab initio 1A＇ ground singlet potential energy surface （Gomez-Carrasco et al 2007 Chem. Phys. Lett. 435 188 193）. The product angular distributions which reflect the vector correlation are calculated. Four polarization-dependent differential cross sections （PDDCSs） which are sensitive to many photoinitiated bimolecular reaction experiments are presented in the center of the mass frame, respectively. The differential cross section indicates that the OH product mainly tends to the forward scattering, and other PDDCSs are also influenced by the vibration levels of HF.
基金Project supported by Young Funding of Jining University,China (Grant No. 2009QNKJ02)
文摘The product polarizations of the title reactions are investigated by employing the quasi-classical trajectory （QCT） method. The four generalized polarization-dependent differential cross-sections （PDDCSs） （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22＋/dωt）, and （2π/σ）（dσ21-/dωt） are calculated in the centre-of-mass frame. The distribution of the angle between κ and j＇, P（θr）, the distribution of the dihedral angle denoting κ-κ＇-j＇ correlation, P（Фr）, as well as the angular distribution of product rotational vectors in the form of polar plots P（θr, Фr） are calculated. The isotope effect is also revealed and primarily attributed to the difference in mass factor between the two title reactions.
文摘Quasiclassical trajectory calculation of the title reaction O（^3P）＋H2→OH＋H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A＂ has been done. Distribution P（θr） of polar angles between the relative velocityk of the reactant and rotational angular momentum vector j＇ of the product, distribution P（φr） of the azimuthal as well as dihedral angles correlating k-k＇-j＇, 3-dimensional distri-bution, and polarization-dependent differential cross sections （PDDCSs）dependent upon the scattering angle of the product molecule OH between the relative velocity k of the reactant and k＇ of the product at different scattering energies of 0.5, 0.75, and 1.0 eV are presented and discussed.
