We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full...We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full vector finite difference method, we investigated the different properties of HN-PCF. Broadband su-percontinuum spectrum is numerically calculated by using nonlinear Schr?dinger equation. Investigation showed that it is possible to obtain longitudinal resolution in a biological tissue of 1.3 μm, 1.2 μm and 1.1 μm by using picosecond continuum light at center wavelengths of 1.06 μm, 1.31 μm and 1.55 μm, respectively.展开更多
This paper studies the interaction of a A-type three-level atom with a single mode field. It discusses the emission spectrum characteristics of the A-type three-level atom driven by the photon-added coherent field. By...This paper studies the interaction of a A-type three-level atom with a single mode field. It discusses the emission spectrum characteristics of the A-type three-level atom driven by the photon-added coherent field. By means of the second-order degree of coherence, it shows some nonclassical properties of the cavity field, such as sub-Poissonian photon- number distribution and the two-time intensity-intensity correlation which violates the Cauchy Schwarz inequality.展开更多
In this work,azulene is introduced into nano-graphene with coronene center to enhance the second-order nonlinear optical(NLO)properties.The sum-over-states(SOS)model based calculations demonstrate that dipolar contrib...In this work,azulene is introduced into nano-graphene with coronene center to enhance the second-order nonlinear optical(NLO)properties.The sum-over-states(SOS)model based calculations demonstrate that dipolar contributions are larger than octupolar contributions to the static first hyperpolarizability(〈β0〉)in most nano-graphenes except those with high symmetry(e.g.,a C2v nano-graphene has octupolar contributionsΦJ=3 up to 59.0%of the〈β0〉).Nano-graphenes containing two parallel orientating azulenes(i.e.,Out-P and Out-Ps)have large dipole moments,while their ground state is triplet.Introducing B/N/BN atoms into the positions with a high spin density transfers the ground state of Out-P and Out-Ps to closed-shell singlet,and the Out-Ps-2N has a large〈β0〉of 1621.67×10−30 esu.Further addition of an electron donor(NH2)at the pentagon end enhances the〈β0〉to 1906.22×10−30 esu.The two-dimensional second-order NLO spectra predicted by using the SOS model find strong sum frequency generations and difference frequency generations,especially in the near-infrared and visible regions.The strategies to stabilize the electronic structure and improve the NLO properties of azulene-defect carbon nanomaterials are proposed,and those strategies to engineer nano-graphenes to be semiconducting while maintaining theπ-framework are exten-dable to other similar systems.展开更多
文摘We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full vector finite difference method, we investigated the different properties of HN-PCF. Broadband su-percontinuum spectrum is numerically calculated by using nonlinear Schr?dinger equation. Investigation showed that it is possible to obtain longitudinal resolution in a biological tissue of 1.3 μm, 1.2 μm and 1.1 μm by using picosecond continuum light at center wavelengths of 1.06 μm, 1.31 μm and 1.55 μm, respectively.
基金supported by the National Natural Science Foundation of China (Grants Nos 10674052 and 60878004)
文摘This paper studies the interaction of a A-type three-level atom with a single mode field. It discusses the emission spectrum characteristics of the A-type three-level atom driven by the photon-added coherent field. By means of the second-order degree of coherence, it shows some nonclassical properties of the cavity field, such as sub-Poissonian photon- number distribution and the two-time intensity-intensity correlation which violates the Cauchy Schwarz inequality.
基金supported by the National Natural Science Foundation of China(Nos.21673025,11974091,21203042,11574062)the Open Projects of Key Laboratory of Polyoxometalate Science of Ministry of Education(NENU)of China and the State Key Laboratory of Supramolecular Structure and Materials(JLU)of China(No.SKLSSM2021020).
文摘In this work,azulene is introduced into nano-graphene with coronene center to enhance the second-order nonlinear optical(NLO)properties.The sum-over-states(SOS)model based calculations demonstrate that dipolar contributions are larger than octupolar contributions to the static first hyperpolarizability(〈β0〉)in most nano-graphenes except those with high symmetry(e.g.,a C2v nano-graphene has octupolar contributionsΦJ=3 up to 59.0%of the〈β0〉).Nano-graphenes containing two parallel orientating azulenes(i.e.,Out-P and Out-Ps)have large dipole moments,while their ground state is triplet.Introducing B/N/BN atoms into the positions with a high spin density transfers the ground state of Out-P and Out-Ps to closed-shell singlet,and the Out-Ps-2N has a large〈β0〉of 1621.67×10−30 esu.Further addition of an electron donor(NH2)at the pentagon end enhances the〈β0〉to 1906.22×10−30 esu.The two-dimensional second-order NLO spectra predicted by using the SOS model find strong sum frequency generations and difference frequency generations,especially in the near-infrared and visible regions.The strategies to stabilize the electronic structure and improve the NLO properties of azulene-defect carbon nanomaterials are proposed,and those strategies to engineer nano-graphenes to be semiconducting while maintaining theπ-framework are exten-dable to other similar systems.
