The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

Yu. S. Chilingaryan - One of the best experts on this subject based on the ideXlab platform.

R. B. Alaverdyan - One of the best experts on this subject based on the ideXlab platform.

  • LASER-INDUCED Thermomechanical EffectS IN NEMATIC LIQUID-CRYSTAL
    International Journal of Modern Physics: Conference Series, 2012
    Co-Authors: A. K. Aleksanyan, R. S. Hakobyan, G. S. Gevorgyan, R. B. Alaverdyan
    Abstract:

    As we know there are several mechanisms allowing us to convert absorbed energy by liquid crystal (LC) to the energy of reorientation of director. One of them is the third Thermomechanical Effect. Third Thermomechanical Effect induced by Gaussian beam was recently studied both theoretically and experimentally. It was shown that Thermomechanical Effects can decrease the threshold of Freedericksz transition in dye-doped nematic liquid crystal (NLC). One of the big advantages of Thermomechanical Effect compared with other mechanisms (for instance giant optical nonlinearity (GON)), which are absent in the case of normal incidence of laser beam, is that it emerges at any angle of incidence of laser beam. Thermomechanical Effects were also studied in NLC, containing azobenzene in their molecular structure. It was suggested that one of the mechanisms of optical nonlinearity observed in the experiment in such medium may be the Thermomechanical Effect.

  • Some Light-Induced Orientational Effects in Nematic Liquid Crystals
    Journal of Physics: Conference Series, 2012
    Co-Authors: R. S. Hakobyan, G. S. Gevorgyan, A. K. Aleksanyan, M. R. Hakobyan, R. B. Alaverdyan
    Abstract:

    Some new light-induced orientational-hydrodynamical nonlinear optical Effects in nematic liquid crystals (NLC) are presented. Among them jump-like light-induced hydrodynamic reorientation caused by direct volume expansion, Thermomechanical oscillations in hybrid NLC and Thermomechanical mechanism of orientational optical nonlinearity in twist aligned NLC as well as in azobenzene liquid crystals. It is also shown that the orientational optical nonlinearity of revealed Thermomechanical Effect may be as strong as well-known giant optical nonlinearity. Besides, at normal incidence of laser the giant optical nonlinearity does not exist, but Thermomechanical Effect exists at any angle of incidence of laser radiation and the nonlinearity of Thermomechanical Effect remains in the same order.

  • Experimental study of laser-induced Thermomechanical Effect and new type of orientational optical nonlinearity in twist aligned nematic liquid crystal
    International Conference on Laser Physics 2010, 2010
    Co-Authors: G. S. Gevorgyan, R. B. Alaverdyan, Albert A. Kirakosyan, R. S. Hakobyan
    Abstract:

    We present theoretical study of the third type Thermomechanical Effect in twist aligned nematic liquid crystal cell. Euler- Lagrange-Rayleigh variation method is applied together with the heat-transfer equation to analyze the laser-induced nonlinearity and director reorientation due to the third type Thermomechanical Effect. Director reorientation due to a transversal 2-dimensional temperature gradient is considered. Director equation is solved numerically and phase shift distribution is presented. It was explained that phase shift is zero in some areas because temperature gradient x and y components compete with each other to reorient the director in opposite directions. It was shown that maximum phase shift is at the same range as that for the Giant Optical Nonlinearity (GON).

  • Light-induced Thermomechanical Effect as a new mechanism of orientational optical nonlinearity in liquid crystals
    JETP Letters, 2010
    Co-Authors: R. S. Hakobyan, R. B. Alaverdyan, G. S. Gevorgyan, Albert A. Kirakosyan
    Abstract:

    A laser-induced Thermomechanical Effect in twist-aligned nematic liquid crystals has been revealed and experimentally studied. It has been proved that the nature of this phenomenon is orientational rather than diffraction. It has been shown that the orientational optical nonlinearity resulting from this Effect can be as strong as the well-known giant optical nonlinearity. Moreover, giant optical nonlinearity does not exist at normal incidence of the laser beam, whereas Thermomechanical nonlinearity remains of the same order of magnitude at any angle of incidence of the beam.

  • Photoinduced Thermomechanical Effect in homogeneous nematics
    Quantum Electronics, 2000
    Co-Authors: R. S. Akopyan, R. B. Alaverdyan, E. A. Santrosyan, Yu. S. Chilingaryan
    Abstract:

    A laser-induced Thermomechanical hydrodynamic flow is theoretically predicted and experimentally detected in a horizontal layer of a nematic liquid crystal with a homogeneous distribution of the director in the presence of vertical temperature gradient. This Effect is caused by the gradient in the director distribution (which is necessary for the usual Thermomechanical Effect) produced by the light field due to photoinduced Freedericksz transition.

R. S. Akopyan - One of the best experts on this subject based on the ideXlab platform.

E. A. Santrosyan - One of the best experts on this subject based on the ideXlab platform.

R. S. Hakobyan - One of the best experts on this subject based on the ideXlab platform.

  • LASER-INDUCED Thermomechanical EffectS IN NEMATIC LIQUID-CRYSTAL
    International Journal of Modern Physics: Conference Series, 2012
    Co-Authors: A. K. Aleksanyan, R. S. Hakobyan, G. S. Gevorgyan, R. B. Alaverdyan
    Abstract:

    As we know there are several mechanisms allowing us to convert absorbed energy by liquid crystal (LC) to the energy of reorientation of director. One of them is the third Thermomechanical Effect. Third Thermomechanical Effect induced by Gaussian beam was recently studied both theoretically and experimentally. It was shown that Thermomechanical Effects can decrease the threshold of Freedericksz transition in dye-doped nematic liquid crystal (NLC). One of the big advantages of Thermomechanical Effect compared with other mechanisms (for instance giant optical nonlinearity (GON)), which are absent in the case of normal incidence of laser beam, is that it emerges at any angle of incidence of laser beam. Thermomechanical Effects were also studied in NLC, containing azobenzene in their molecular structure. It was suggested that one of the mechanisms of optical nonlinearity observed in the experiment in such medium may be the Thermomechanical Effect.

  • Some Light-Induced Orientational Effects in Nematic Liquid Crystals
    Journal of Physics: Conference Series, 2012
    Co-Authors: R. S. Hakobyan, G. S. Gevorgyan, A. K. Aleksanyan, M. R. Hakobyan, R. B. Alaverdyan
    Abstract:

    Some new light-induced orientational-hydrodynamical nonlinear optical Effects in nematic liquid crystals (NLC) are presented. Among them jump-like light-induced hydrodynamic reorientation caused by direct volume expansion, Thermomechanical oscillations in hybrid NLC and Thermomechanical mechanism of orientational optical nonlinearity in twist aligned NLC as well as in azobenzene liquid crystals. It is also shown that the orientational optical nonlinearity of revealed Thermomechanical Effect may be as strong as well-known giant optical nonlinearity. Besides, at normal incidence of laser the giant optical nonlinearity does not exist, but Thermomechanical Effect exists at any angle of incidence of laser radiation and the nonlinearity of Thermomechanical Effect remains in the same order.

  • Experimental study of laser-induced Thermomechanical Effect and new type of orientational optical nonlinearity in twist aligned nematic liquid crystal
    International Conference on Laser Physics 2010, 2010
    Co-Authors: G. S. Gevorgyan, R. B. Alaverdyan, Albert A. Kirakosyan, R. S. Hakobyan
    Abstract:

    We present theoretical study of the third type Thermomechanical Effect in twist aligned nematic liquid crystal cell. Euler- Lagrange-Rayleigh variation method is applied together with the heat-transfer equation to analyze the laser-induced nonlinearity and director reorientation due to the third type Thermomechanical Effect. Director reorientation due to a transversal 2-dimensional temperature gradient is considered. Director equation is solved numerically and phase shift distribution is presented. It was explained that phase shift is zero in some areas because temperature gradient x and y components compete with each other to reorient the director in opposite directions. It was shown that maximum phase shift is at the same range as that for the Giant Optical Nonlinearity (GON).

  • Light-induced Thermomechanical Effect as a new mechanism of orientational optical nonlinearity in liquid crystals
    JETP Letters, 2010
    Co-Authors: R. S. Hakobyan, R. B. Alaverdyan, G. S. Gevorgyan, Albert A. Kirakosyan
    Abstract:

    A laser-induced Thermomechanical Effect in twist-aligned nematic liquid crystals has been revealed and experimentally studied. It has been proved that the nature of this phenomenon is orientational rather than diffraction. It has been shown that the orientational optical nonlinearity resulting from this Effect can be as strong as the well-known giant optical nonlinearity. Moreover, giant optical nonlinearity does not exist at normal incidence of the laser beam, whereas Thermomechanical nonlinearity remains of the same order of magnitude at any angle of incidence of the beam.

  • Director reorientation in twisted nematic liquid crystals due to Thermomechanical Effect
    Physics Letters A, 2008
    Co-Authors: J. B. Poursamad, R. S. Hakobyan
    Abstract:

    We have studied molecular director reorientation in a twisted nematic liquid crystal induced by a two-dimensional temperature gradient. We studied the Effect of rate change between the temperature gradients in two directions. Our obtained director reorientations are in the range that can be observed experimentally very easily.