We report the modulational instability （MI） analysis for the modulation equations governing the propagation of coherent polarized light through a nematic liquid crystal （NLC） slab, in the limit of low light intens...We report the modulational instability （MI） analysis for the modulation equations governing the propagation of coherent polarized light through a nematic liquid crystal （NLC） slab, in the limit of low light intensity and local material response. The linear stability analysis of the nonlinear plane wave solutions is performed by considering both the wave vectors （k,l） of the basic states and wave vectors （K,L） of the perturbations as free parameters. We compute the MI gain, and the MI gain peak is reduced and the stable bandwidth is widened with the increase of the strength of the applied electric field. Further, we invoke the extended homogeneous balance method and Exp-function method aided with symbolic computation and obtain a series of periodic solitonic humps of nematicon profiles admitting the propagation of laser light in the NLC medium.展开更多
Investigated in this paper is the generalized nonlinear Schrdinger equation with radial symmetry.Withthe help of symbolic computation, the one-, two-, and N-soliton solutions are obtained through the bilinear metho...Investigated in this paper is the generalized nonlinear Schrdinger equation with radial symmetry.Withthe help of symbolic computation, the one-, two-, and N-soliton solutions are obtained through the bilinear method.Bcklund transformation in the bilinear form is presented, through which a new solution is constructed.Graphically, wehave found that the solitons are symmetric about x=0, while the soliton pulse width and amplitude will change alongwith the distance and time during the propagation.展开更多
The thermo-order-mechanical behaviors of liquid crystal elastomers （LCEs） under biaxial loading are studied in this paper. Inverse method for nonlinear elastic problems is utilized by imposing biaxial stretching to ...The thermo-order-mechanical behaviors of liquid crystal elastomers （LCEs） under biaxial loading are studied in this paper. Inverse method for nonlinear elastic problems is utilized by imposing biaxial stretching to thin rectangular samples. Neo-classical elastic energy is used together with the Landau-de Gennes nematic free energy. Under plane stress assumptions, the constitutive equations are derived. Due to the possible reorientations of the liquid crystal molecules induced by the imposed biaxial loading, the in-plane nonlinear stress-strain relations can have different expressions depending on which loading axis will have the largest effective principal strain. And the free energy is a multi-well non-convex potential function. As shown by some typical loading paths, the LCE samples will exhibit an anisotropic nonlinear elastic behavior, as long as the loading has not induced a reorientation of the liquid crystal molecules. When this did occur, jumps of stresses could take place for dead loadings due to the losing of stability.展开更多
In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy （SNOM）. Optical writing and subsequently topographic reading of the patterns w...In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy （SNOM）. Optical writing and subsequently topographic reading of the patterns with subwavelength resolution were carried out in our experiments. Nanometer scale dots and lines were successfully fabricated on the films and the smallest dot diameter is about 120 nm. The width of the line fabricated is about 250 nm. This method is also a choice for nanolithography. The mechanism of the surface deformation on the polymer films was briefly analyzed from the viewpoint of gradient force in the optical near field. The intensity distribution of the electric field near the tip aperture was numerically simulated using finite-difference time-domain （FDTD） method and the numerical simulation results were consistent with the experimental results.展开更多
In birefringent optical fibers, the propagation of femtosecond soliton pulses is described by coupled higherorder nonlinear Schrdinger equations. In this paper, we will investigate the bright and dark soliton soluti...In birefringent optical fibers, the propagation of femtosecond soliton pulses is described by coupled higherorder nonlinear Schrdinger equations. In this paper, we will investigate the bright and dark soliton solutions of(2+1)-dimensional coupled higher-order nonlinear Schrdinger equations, with the aid of symbolic computation and the Hirota method. On the basis of soliton solutions, we test and discuss the interactions graphically between the solitons in the x-z, x-t, and z-t planes.展开更多
A new type ultraflattened dispersion square-lattice photonic crystal fiber with two different air-hole diameters in cladding region is proposed and the dispersion is investigated using a compact 2-D finite difference ...A new type ultraflattened dispersion square-lattice photonic crystal fiber with two different air-hole diameters in cladding region is proposed and the dispersion is investigated using a compact 2-D finite difference frequency domain method with the anisotropic perfectly matched layers (PML) absorbing boundary conditions. Through numerical simulation and opti- mizing the geometrical parameters, we find that the photonic crystal fibers proposed can realize ultraflattened dispersion of 0±0.06 ps/(km·nm) in wavelength range of 1.375 μm to 1.605 μm, which is more flat than that of triangular PCF, and the confinement loss is as low as about 0.01 dB/km at wavelength of 1.55 μm.展开更多
基金One of the authors (L. Kavitha) gratefully acknowledges the financial support from NBHM, India in the form of major research project, BRNS, India in the form of Young Scientist Research Award and ICTP, Italy in the form of Junior AssociateshipUGC, India for financial assistance in the form of Research Award+1 种基金M. Venkatesh acknowledges BSR-Research Fellowship under UGC Non-SAP Scheme, IndiaS. Dhamayanthi thanks the University Research Fellowship (URF) given by Periyar Uni- versity, India.
文摘We report the modulational instability （MI） analysis for the modulation equations governing the propagation of coherent polarized light through a nematic liquid crystal （NLC） slab, in the limit of low light intensity and local material response. The linear stability analysis of the nonlinear plane wave solutions is performed by considering both the wave vectors （k,l） of the basic states and wave vectors （K,L） of the perturbations as free parameters. We compute the MI gain, and the MI gain peak is reduced and the stable bandwidth is widened with the increase of the strength of the applied electric field. Further, we invoke the extended homogeneous balance method and Exp-function method aided with symbolic computation and obtain a series of periodic solitonic humps of nematicon profiles admitting the propagation of laser light in the NLC medium.
基金Supported by the National Natural Science Foundation of China under Grant No.60772023the Open Fund (No.BUAASKLSDE-09KF-04)+2 种基金Supported Project (No.SKLSDE-2010ZX-07) of the State Key Laboratory of Software Development Environment,Beijing University of Aeronautics and Astronauticsthe National Basic Research Program of China (973 Program) under Grant No.2005CB321901the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.200800130006,Chinese Ministry of Education
文摘Investigated in this paper is the generalized nonlinear Schrdinger equation with radial symmetry.Withthe help of symbolic computation, the one-, two-, and N-soliton solutions are obtained through the bilinear method.Bcklund transformation in the bilinear form is presented, through which a new solution is constructed.Graphically, wehave found that the solitons are symmetric about x=0, while the soliton pulse width and amplitude will change alongwith the distance and time during the propagation.
基金supported by National Natural Science Foundation of China (Nos. 11072062 and 11172068)the Research Fund for the Doctoral Program of Higher Education of China (No. 20110071110013)
文摘The thermo-order-mechanical behaviors of liquid crystal elastomers （LCEs） under biaxial loading are studied in this paper. Inverse method for nonlinear elastic problems is utilized by imposing biaxial stretching to thin rectangular samples. Neo-classical elastic energy is used together with the Landau-de Gennes nematic free energy. Under plane stress assumptions, the constitutive equations are derived. Due to the possible reorientations of the liquid crystal molecules induced by the imposed biaxial loading, the in-plane nonlinear stress-strain relations can have different expressions depending on which loading axis will have the largest effective principal strain. And the free energy is a multi-well non-convex potential function. As shown by some typical loading paths, the LCE samples will exhibit an anisotropic nonlinear elastic behavior, as long as the loading has not induced a reorientation of the liquid crystal molecules. When this did occur, jumps of stresses could take place for dead loadings due to the losing of stability.
基金This work was supported by the National Natural Science Foundation of China (No. 90206002) theNational and Development Program of China (No.2002AA313030) the Provincial Natural Science Foundation of Anhui (No. 03046204)
文摘In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy （SNOM）. Optical writing and subsequently topographic reading of the patterns with subwavelength resolution were carried out in our experiments. Nanometer scale dots and lines were successfully fabricated on the films and the smallest dot diameter is about 120 nm. The width of the line fabricated is about 250 nm. This method is also a choice for nanolithography. The mechanism of the surface deformation on the polymer films was briefly analyzed from the viewpoint of gradient force in the optical near field. The intensity distribution of the electric field near the tip aperture was numerically simulated using finite-difference time-domain （FDTD） method and the numerical simulation results were consistent with the experimental results.
基金Supported by the National Natural Science Foundation of China under Grant No.61671227the Natural Science Foundation of Shandong Province under Grant No.ZR2014AM018
文摘In birefringent optical fibers, the propagation of femtosecond soliton pulses is described by coupled higherorder nonlinear Schrdinger equations. In this paper, we will investigate the bright and dark soliton solutions of(2+1)-dimensional coupled higher-order nonlinear Schrdinger equations, with the aid of symbolic computation and the Hirota method. On the basis of soliton solutions, we test and discuss the interactions graphically between the solitons in the x-z, x-t, and z-t planes.
基金supported by the National Natural ScienceFoundation of China (Grant Nos. 60637010 and 60671036)the National Basic Research Program of China (Grant No.2007CB310403).
文摘A new type ultraflattened dispersion square-lattice photonic crystal fiber with two different air-hole diameters in cladding region is proposed and the dispersion is investigated using a compact 2-D finite difference frequency domain method with the anisotropic perfectly matched layers (PML) absorbing boundary conditions. Through numerical simulation and opti- mizing the geometrical parameters, we find that the photonic crystal fibers proposed can realize ultraflattened dispersion of 0±0.06 ps/(km·nm) in wavelength range of 1.375 μm to 1.605 μm, which is more flat than that of triangular PCF, and the confinement loss is as low as about 0.01 dB/km at wavelength of 1.55 μm.
