Self-starting laser with cavity completed by dynamic holographic grating induced in a nematic liquid crystal near phase transition point

2000 ◽  
Author(s):  
A.S. Kuzhelev ◽  
A.P. Zinov'ev ◽  
O.N. Eremeykin ◽  
O.L. Antipov ◽  
R. Macdonald
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Transition Point ◽  
Phase Transition Point ◽  
Holographic Grating

scholarly journals Dissipative structures induced by photoisomerization in a dye-doped nematic liquid crystal layer

2018 ◽  
Vol 376 (2135) ◽  
pp. 20170382 ◽  
Author(s):  
I. Andrade-Silva ◽  
U. Bortolozzo ◽  
C. Castillo-Pinto ◽  
M. G. Clerc ◽  
G. González-Cortés ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Dissipative Structures ◽  
Input Power ◽  
Isotropic Phase ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Nematic Liquid Crystal Layer ◽  
Interface Propagation

Order–disorder phase transitions driven by temperature or light in soft matter materials exhibit complex dissipative structures. Here, we investigate the spatio-temporal phenomena induced by light in a dye-doped nematic liquid crystal layer. Experimentally, for planar anchoring of the nematic layer and high enough input power, photoisomerization processes induce a nematic–isotropic phase transition mediated by interface propagation between the two phases. In the case of a twisted nematic layer and for intermediate input power, the light induces a spatially modulated phase, which exhibits stripe patterns. The pattern originates as an instability mediated by interface propagation between the modulated and the homogeneous nematic states. Theoretically, the phase transition, emergence of stripe patterns and front dynamics are described on the basis of a proposed model for the dopant concentration coupled with the nematic order parameter. Numerical simulations show quite a fair agreement with the experimental observations. This article is part of the theme issue ‘Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 2)’.

scholarly journals Распространение поверхностной магнитоупругой волны в ферромагнетике в области ориентационного фазового перехода

2020 ◽  
Vol 62 (6) ◽  
pp. 851
Author(s):  
И.В. Мальцев ◽  
И.В. Бычков ◽  
Д.А. Кузьмин ◽  
В.Г. Шавров
Keyword(s):  
Phase Transition ◽  
Group Velocity ◽  
Yttrium Iron Garnet ◽  
Transition Point ◽  
Phase Transition Point ◽  
Yttrium Iron ◽  
Orientational Phase Transition ◽  
Velocity Changes ◽  
Iron Garnet ◽  
Magnetoelastic Surface

In this paper, we have studied the dependencies of group velocity and damping of magnetoelastic surface waves on the frequency at various external magnetic fields and propagation angles. The group velocity spikes occur at frequencies at which the damping peaks of the surface wave are detected. The behavior of a surface magnetoelastic wave in the vicinity of the orientational phase transition was also investigated. At the phase transition point, the group velocity changes by 1%. Dependences of the damping along the surface at various propagation angles point out on the nonreciprocal nature of the wave. All dependencies in this work were obtained using computer modeling. The parameters of the ferromagnet are taken typical for yttrium-iron garnet.

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