This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the op...This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution, and transverse velocity of these grey solitons are discussed.展开更多
In a biased photorefractive crystal, the process of two one-dimensional waves mixing, i.e., the dynamical evolution of both pump beam and signal beam, is traced by numerically solving the coupled-wave equation. Direct...In a biased photorefractive crystal, the process of two one-dimensional waves mixing, i.e., the dynamical evolution of both pump beam and signal beam, is traced by numerically solving the coupled-wave equation. Direct simulations show that the propagation and stability of the two beams are completely determined by the system parameters, such as the external bias field, the intensity and the beam waist of the pump beam. By adjusting these parameters, one can control the state of two Gaussian waves mixing. The numerical results are helpful for performing a two-wave mixing experiment.展开更多
The generation and propagation characteristics of bright spatial bound-soliton pairs (BSPs) are investigated under the diffusion effect in photovoltaic photorefractive crystals by numerical simulation. The results sho...The generation and propagation characteristics of bright spatial bound-soliton pairs (BSPs) are investigated under the diffusion effect in photovoltaic photorefractive crystals by numerical simulation. The results show that two coherent solitons, one as the signal light and the other as the control light, can form a BSP when the peak intensity of the control light is appropriately selected. Moreover, under the diffusion effect, the BSP experiences a self-bending process during propagating and the center of the BSP moves on a parabolic trajectory. Furthermore, the lateral shift of the BSP at the output face of the crystal can be manipulated by adjusting the peak intensity of the control light. The research results provide a method for the design of all-optical switching and routing based on the manipulation of the lateral position of BSPs.展开更多
This paper investigates the photorefractive properties of iron doped lithium niobate with different [Li]/[Nb] ratios The experimental results show two photorefractive centres for iron doped near-stoichiometric lithium...This paper investigates the photorefractive properties of iron doped lithium niobate with different [Li]/[Nb] ratios The experimental results show two photorefractive centres for iron doped near-stoichiometric lithium niobate crystal Besides Fe^2＋ and Fe^3＋ ions, small polarons and bipolarons are considered as another photoactive centre.展开更多
Holographic dark （bright） screening solitons are predicted in one dimension for a series circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage sourc...Holographic dark （bright） screening solitons are predicted in one dimension for a series circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage source. Each crystal can support a holographic screening soliton. The two solitons are known collectively as a separate holographic screening soliton pair with three types： bright-bright, bright-dark and dark-dark. The numerical results show that the two solitons in a soliton pair can affect each other through a light-induced current and their coupling can affect their spatial profiles under the limit in which the optical wave has a spatial extent much less than the width of the crystal.展开更多
The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between...The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between one- and two-dimensional solitons, whose attractive and repulsive effects depend on the soliton separation, is numerically demonstrated by employing an anisotropic model. By launching a one-dimensional green beam and a two-dimensional red beam into a biased SBN：60 crystal, the hybrid-dimensional soliton interaction is performed. The experimental results are in good agreement with the numerical ones.展开更多
This paper reports that when an intense extraordinary-polarized laser beam illuminates a photorefractive BaTiO3 crystal, the dynamic beam fanning light is formed to be a thermal-like light source with a long correlati...This paper reports that when an intense extraordinary-polarized laser beam illuminates a photorefractive BaTiO3 crystal, the dynamic beam fanning light is formed to be a thermal-like light source with a long correlation time and wide spectral bandwidth. The experimental results of the first- and second-order double-slit interference with such photorefractive fanning light source, cart be understood with the theoretical simulation in terms of Hanbury-Brown and Twiss effect.展开更多
Time-dependent hybrid density functional theory in combination with polarized continuum model is applied to study the solvent effects on the geometrical and electronic structures as well as one- and two-photon absorpt...Time-dependent hybrid density functional theory in combination with polarized continuum model is applied to study the solvent effects on the geometrical and electronic structures as well as one- and two-photon absorption processes, of a newly synthesized asymmetrical charge-transfer organic molecule bis-（4-bromo-phenyl）-[4-（2-pyridin-4-yl-vinyl）phenyl]-amine （BPYPA）. There exist two charge-transfer states for the compound in visible region. The two-photon absorption cross section calculated by a three-state model and solvatochromic shift of the charge-transfer states are found to be solvent-dependent, where a nonmonotonic behaviour with respect to the polarity of the solvents is observed. The numerical results show that the organic molecule exhibits a rather large two-photon absorption cross section as compared with the compound 4-trans-[p-（N, N-Di-n-butylamino）-p-stilbenyl vinyl] pyridine （DBASVP） reported previously, and is predicted to be a good two-photon polymerization initiator. The hydrogen-bond effect is analysed. The computational results are in good agreement with the measurements.展开更多
This paper has theoretically designed a series of aggregate polymers on the basis of several para-nitroaniline monomers by hydrogen-bond interactions. At the level of time-dependent hybrid density functional theory, i...This paper has theoretically designed a series of aggregate polymers on the basis of several para-nitroaniline monomers by hydrogen-bond interactions. At the level of time-dependent hybrid density functional theory, it has optimized their geometrical structures and studied their two-photon absorption （TPA） properties by using analytical response theory. The calculated results exhibit that the aggregation effects not only bring out the conaiderable red shift of the excited energies but also greatly enhance the TPA intensities of the aggregate polymers in comparison with the para-nitroaniline monomer. The aggregate configurations also have an important influence on the TPA abilities of the polymers; the trimer has the largest TPA cross section. The electron transitions between the molecular orbits involving the strong TPA excitations of the trimer are depicted to illuminate the relationship between the intermolecular charge transfer and the TPA property.展开更多
We present a two-photon interference experiment in a modified Mach-Zehnder （MZ） interferometer in which two Hong-Ou-Mandel effects occur in tandem and construct superposed two-photon states. The signal photons pass ...We present a two-photon interference experiment in a modified Mach-Zehnder （MZ） interferometer in which two Hong-Ou-Mandel effects occur in tandem and construct superposed two-photon states. The signal photons pass both the arms of the MZ interferometer while the idler photons pass one arm only. Interestingly, the probability of the idler photons emerging from any output port still shows a sine oscillation with the two-photon phase difference and it can be characterized only by the indistinguishability of the two-photon amplitudes. We also observe a two-photon interference pattern with a period being equal to the wavelength of the parametric photons instead of the two-photon photonie de Broglie wavelength due to the presence of two-photon phase difference, in particular, with complementary probabilities of finding the two-photon pairs in two output ports. The abundant observations can facilitate a more comprehensive understanding of the two-photon interference.展开更多
We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical re...We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright-dark soliton pair originally formed in a crystal circuit at given temperatures, when one crystal temperature changes, the soliton supported by the other crystal will evolve into another stable soliton if the temperature change is quite small, whereas it will become unstable and experience larger cycles of compression or break up into beam filaments if the temperature difference is big enough. The dark soliton is more sensitive to the temperature change than the bright one.展开更多
Aggregation effect caused by the intermolecular hydrogen-bonding interactions on two-photon absorption prop- erties of （E）-4-（2-nitrovinyl） benzenamine molecules is studied at a hybrid density functional level. Th...Aggregation effect caused by the intermolecular hydrogen-bonding interactions on two-photon absorption prop- erties of （E）-4-（2-nitrovinyl） benzenamine molecules is studied at a hybrid density functional level. The geometry optimization studies indicate that there exist two probable conformations for the dimers and three for the trimers. A strong red-shift of the charge-transfer states is shown. The two-photon absorption cross sections of the molecule for certain conformations are greatly enhanced by the aggregation effect, from which a ratio of 1.0：2.6：3.6 is found for the molecule and its dimer and trimer with nearly planar structures. Namely, a 30 or 20 percent increase of the two-photon absorption cross section is observed.展开更多
Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid （HOC1） are investigated by employing time-dependent density functional theory. The computational resul...Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid （HOC1） are investigated by employing time-dependent density functional theory. The computational results show that the absorption and emission properties of these probes change obviously when they react with hypochlorous acid. It is found that the probe FHZ has the best performance according to the probing behavior. Moreover, the responsive mechanisms of the probes are studied by analyzing the distributions of molecular orbitals and charge transfer, which are shown as the photon- induced electron transfer （PET） for FHZ and the intramolecular charge transfer OCT） for the other two probes. Specially, solvent effect on optical properties of the probe FHZ before and after reaction is studied within the polarizable continuum model （PCM）. It is shown that performance of the probe depends crucially on the solvent polarity. Our computational results agree well with the experimental measurement, and provide information for design of efficient two-photon fluorescent probes.展开更多
Time-dependent hybrid density functional theory in combination with Onsager reaction field model and super-molecular model has been applied to study solvent effects on the geometrical and electronic structures, as wel...Time-dependent hybrid density functional theory in combination with Onsager reaction field model and super-molecular model has been applied to study solvent effects on the geometrical and electronic structures, as well as one/two-photon absorption properties, of 4-（N-（2-hydroxyethyl）-N-methyl）-amino-4＇-nitroazobenzene. It is found that the short-range interaction has a large effect on the electronic structure of the solute molecule, namely, large red-shift of the maximum one-photon absorption is induced by hydrogen bonding. The solute molecule has a large two-photon absorption cross section, which is enhanced by the solvent effect. The computational results are in good agreement with measurements.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 60508005）, and Scientific Research Foundation of Harbin Institute of Technology of China （Grant No HIT. 2003. 31）.
文摘This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution, and transverse velocity of these grey solitons are discussed.
基金supported by the National Natural Science Foundations of China(Grant Nos 10174025 and 10574051)
文摘In a biased photorefractive crystal, the process of two one-dimensional waves mixing, i.e., the dynamical evolution of both pump beam and signal beam, is traced by numerically solving the coupled-wave equation. Direct simulations show that the propagation and stability of the two beams are completely determined by the system parameters, such as the external bias field, the intensity and the beam waist of the pump beam. By adjusting these parameters, one can control the state of two Gaussian waves mixing. The numerical results are helpful for performing a two-wave mixing experiment.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61875058, 11874018, 11974006, and 61378036).
文摘The generation and propagation characteristics of bright spatial bound-soliton pairs (BSPs) are investigated under the diffusion effect in photovoltaic photorefractive crystals by numerical simulation. The results show that two coherent solitons, one as the signal light and the other as the control light, can form a BSP when the peak intensity of the control light is appropriately selected. Moreover, under the diffusion effect, the BSP experiences a self-bending process during propagating and the center of the BSP moves on a parabolic trajectory. Furthermore, the lateral shift of the BSP at the output face of the crystal can be manipulated by adjusting the peak intensity of the control light. The research results provide a method for the design of all-optical switching and routing based on the manipulation of the lateral position of BSPs.
基金Project supported by the research funding via Program for Changjiang Scholars of ChinaInnovative Research Team in University,China+1 种基金the National Natural Science Foundation of China(Grant No60578019)Program for Changjiang Scholars and Innovative Research Team in University
文摘This paper investigates the photorefractive properties of iron doped lithium niobate with different [Li]/[Nb] ratios The experimental results show two photorefractive centres for iron doped near-stoichiometric lithium niobate crystal Besides Fe^2＋ and Fe^3＋ ions, small polarons and bipolarons are considered as another photoactive centre.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10174025 and 10574051)
文摘Holographic dark （bright） screening solitons are predicted in one dimension for a series circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage source. Each crystal can support a holographic screening soliton. The two solitons are known collectively as a separate holographic screening soliton pair with three types： bright-bright, bright-dark and dark-dark. The numerical results show that the two solitons in a soliton pair can affect each other through a light-induced current and their coupling can affect their spatial profiles under the limit in which the optical wave has a spatial extent much less than the width of the crystal.
基金Project supported by the Doctoral Science Foundation of Northwestern Polytechnical University (NPU),China (Grant No. CX200514)the NPU Foundation for Fundamental Research,China
文摘The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between one- and two-dimensional solitons, whose attractive and repulsive effects depend on the soliton separation, is numerically demonstrated by employing an anisotropic model. By launching a one-dimensional green beam and a two-dimensional red beam into a biased SBN：60 crystal, the hybrid-dimensional soliton interaction is performed. The experimental results are in good agreement with the numerical ones.
基金Project supported by the National Fundamental Research Program of China （Project No 2001CB309310）, and the National Natural Science Foundation of China （Project No 10574015）.Acknowledgment 0ne of the authors, Wang Kaige, acknowledges the financial support of the Abdus Salam International Centre for Theoretical Physics （ICTP） under the Associate Programme.
文摘This paper reports that when an intense extraordinary-polarized laser beam illuminates a photorefractive BaTiO3 crystal, the dynamic beam fanning light is formed to be a thermal-like light source with a long correlation time and wide spectral bandwidth. The experimental results of the first- and second-order double-slit interference with such photorefractive fanning light source, cart be understood with the theoretical simulation in terms of Hanbury-Brown and Twiss effect.
基金Project supported by the National Natural Science Foundation of China （Grant No 10274044） and Shandong Natural Science Foundation （Grant No Y2004A08）.
文摘Time-dependent hybrid density functional theory in combination with polarized continuum model is applied to study the solvent effects on the geometrical and electronic structures as well as one- and two-photon absorption processes, of a newly synthesized asymmetrical charge-transfer organic molecule bis-（4-bromo-phenyl）-[4-（2-pyridin-4-yl-vinyl）phenyl]-amine （BPYPA）. There exist two charge-transfer states for the compound in visible region. The two-photon absorption cross section calculated by a three-state model and solvatochromic shift of the charge-transfer states are found to be solvent-dependent, where a nonmonotonic behaviour with respect to the polarity of the solvents is observed. The numerical results show that the organic molecule exhibits a rather large two-photon absorption cross section as compared with the compound 4-trans-[p-（N, N-Di-n-butylamino）-p-stilbenyl vinyl] pyridine （DBASVP） reported previously, and is predicted to be a good two-photon polymerization initiator. The hydrogen-bond effect is analysed. The computational results are in good agreement with the measurements.
基金Project supported by the State Key Development Program for Basic Research of China(Grant No.2006CB806000)the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)Natural Science Foundation of Shandong Province of China(Grant No.Z2007A02)
文摘This paper has theoretically designed a series of aggregate polymers on the basis of several para-nitroaniline monomers by hydrogen-bond interactions. At the level of time-dependent hybrid density functional theory, it has optimized their geometrical structures and studied their two-photon absorption （TPA） properties by using analytical response theory. The calculated results exhibit that the aggregation effects not only bring out the conaiderable red shift of the excited energies but also greatly enhance the TPA intensities of the aggregate polymers in comparison with the para-nitroaniline monomer. The aggregate configurations also have an important influence on the TPA abilities of the polymers; the trimer has the largest TPA cross section. The electron transitions between the molecular orbits involving the strong TPA excitations of the trimer are depicted to illuminate the relationship between the intermolecular charge transfer and the TPA property.
基金Supported by the National Key R&D Program of China under Grant Nos 2017YFA0303800 and 2017YFA0303700the National Natural Science Foundation of China under Grant Nos 11534006,11774183 and 11674184+1 种基金the Natural Science Foundation of Tianjin under Grant No 16JCZDJC31300the Collaborative Innovation Center of Extreme Optics
文摘We present a two-photon interference experiment in a modified Mach-Zehnder （MZ） interferometer in which two Hong-Ou-Mandel effects occur in tandem and construct superposed two-photon states. The signal photons pass both the arms of the MZ interferometer while the idler photons pass one arm only. Interestingly, the probability of the idler photons emerging from any output port still shows a sine oscillation with the two-photon phase difference and it can be characterized only by the indistinguishability of the two-photon amplitudes. We also observe a two-photon interference pattern with a period being equal to the wavelength of the parametric photons instead of the two-photon photonie de Broglie wavelength due to the presence of two-photon phase difference, in particular, with complementary probabilities of finding the two-photon pairs in two output ports. The abundant observations can facilitate a more comprehensive understanding of the two-photon interference.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10574051 and 10174025） and the Research Foundation for 0utstanding Young Teachers, China University of Geosciences （Grant No CUGQNL0621）.
文摘We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright-dark soliton pair originally formed in a crystal circuit at given temperatures, when one crystal temperature changes, the soliton supported by the other crystal will evolve into another stable soliton if the temperature change is quite small, whereas it will become unstable and experience larger cycles of compression or break up into beam filaments if the temperature difference is big enough. The dark soliton is more sensitive to the temperature change than the bright one.
基金Project supported by the National Basic Research Program of China (Grant No. 2006CB806000)the Open Fund of the State Key Laboratory of High Field Laser Physics (Shanghai Institute of Optics and Fine Mechanics)the National Natural Science Foundation of China (Grant No. 10974121)
文摘Aggregation effect caused by the intermolecular hydrogen-bonding interactions on two-photon absorption prop- erties of （E）-4-（2-nitrovinyl） benzenamine molecules is studied at a hybrid density functional level. The geometry optimization studies indicate that there exist two probable conformations for the dimers and three for the trimers. A strong red-shift of the charge-transfer states is shown. The two-photon absorption cross sections of the molecule for certain conformations are greatly enhanced by the aggregation effect, from which a ratio of 1.0：2.6：3.6 is found for the molecule and its dimer and trimer with nearly planar structures. Namely, a 30 or 20 percent increase of the two-photon absorption cross section is observed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11374195 and 11404193)the Taishan Scholar Program of Shandong Province,China
文摘Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid （HOC1） are investigated by employing time-dependent density functional theory. The computational results show that the absorption and emission properties of these probes change obviously when they react with hypochlorous acid. It is found that the probe FHZ has the best performance according to the probing behavior. Moreover, the responsive mechanisms of the probes are studied by analyzing the distributions of molecular orbitals and charge transfer, which are shown as the photon- induced electron transfer （PET） for FHZ and the intramolecular charge transfer OCT） for the other two probes. Specially, solvent effect on optical properties of the probe FHZ before and after reaction is studied within the polarizable continuum model （PCM）. It is shown that performance of the probe depends crucially on the solvent polarity. Our computational results agree well with the experimental measurement, and provide information for design of efficient two-photon fluorescent probes.
基金Project supported by the National Natural Science Foundation of China （Grant No 10674084）.
文摘Time-dependent hybrid density functional theory in combination with Onsager reaction field model and super-molecular model has been applied to study solvent effects on the geometrical and electronic structures, as well as one/two-photon absorption properties, of 4-（N-（2-hydroxyethyl）-N-methyl）-amino-4＇-nitroazobenzene. It is found that the short-range interaction has a large effect on the electronic structure of the solute molecule, namely, large red-shift of the maximum one-photon absorption is induced by hydrogen bonding. The solute molecule has a large two-photon absorption cross section, which is enhanced by the solvent effect. The computational results are in good agreement with measurements.
