Influence of the magnetic field on the rotation of light polarization plane in the cholesteric liquid crystal

Abstract A few microns thick layer of an optically active cholesteric liquid crystal is realized by using a photoisomerizable nematic component and a chiral dopant. It is shown that such a photosensitive optically active medium can be used as a holographic material for optical information and dynamic grating recording. The photo-induced gratings are written by exploiting the light-induced photoisomerization phase transition from an optically active chiral liquid crystal to an isotropic liquid, which results in the rotation of the light polarization plane from 90 to 0 degrees and corresponding to maximum, respectively, zero transmittance. The results highlight applications in the field of optical storage by the recording of static gratings, as well as in the feld of nonlinear beam-coupling via the holographic writing of dynamic gratings

Download Full-text

Effect of static magnetic field on the helical flow of incompressible cholesteric liquid crystal between two coxial circular cylinders having rotational and axial velocities

The Journal of the Australian Mathematical Society Series B Applied Mathematics ◽

10.1017/s0334270000001223 ◽

1976 ◽

Vol 19 (3) ◽

pp. 371-380

Author(s):

G. Paria ◽

A. K. Sharma

Keyword(s):

Magnetic Field ◽

Liquid Crystal ◽

Angular Velocity ◽

Static Magnetic Field ◽

Axial Velocity ◽

Cholesteric Liquid Crystal ◽

Helical Flow ◽

Circular Cylinders ◽

The Magnetic Field ◽

Orientation Of Molecules

AbstractThe paper investigates the effect of a static magnetic field on the helical flow of an incompressible cholestenc liquid crystal with director of unit magnitude between two coaxial circular cylinders rotating with different angular velocities about their common axis and moving with different axial velocities. At low shear rates with a weak magnetic field in the axial direction, the axial velocity, the angular velocity and the orientation of molecules between the two cylinders have been obtained. It is found that the magnetic field has influenced the orientation of molecules while the axial velocity and the angular velocity remain uneffected by the magnetic field.

Download Full-text

Dynamics of a disc in a nematic liquid crystal

Soft Matter ◽

10.1039/c5sm02333e ◽

2016 ◽

Vol 12 (4) ◽

pp. 1279-1294 ◽

Cited By ~ 11

Author(s):

Alena Antipova ◽

Colin Denniston

Keyword(s):

Magnetic Field ◽

Liquid Crystal ◽

Numerical Simulations ◽

Nematic Liquid Crystal ◽

Weak Magnetic Field ◽

Angular Speed ◽

The Magnetic Field

We explain the motion of a micron-sized ferromagnetic disc immersed in a nematic liquid crystal under the action of a weak magnetic field using numerical simulations. We show that the disc's behaviour can be controlled by the angular speed of the magnetic field and its magnitude.

Download Full-text

Light-Controlled Rotation of the Light Polarization Plane in Weakly Twisted Nematics

Molecular Crystals and Liquid Crystals Science and Technology Section A Molecular Crystals and Liquid Crystals ◽

10.1080/10587259508033462 ◽

1995 ◽

Vol 261 (1) ◽

pp. 159-165 ◽

Cited By ~ 1

Author(s):

Andrey G. Iljin ◽

Gertruda V. Klimusheva ◽

Victor Yu. Reshetnyak ◽

Yu A. Reznikov

Keyword(s):

Polarization Plane ◽

Light Polarization ◽

Light Polarization Plane

Download Full-text

Photons in a cold axion background and strong magnetic fields: Polarimetric consequences

International Journal of Modern Physics A ◽

10.1142/s0217751x15500992 ◽

2015 ◽

Vol 30 (17) ◽

pp. 1550099 ◽

Cited By ~ 6

Author(s):

Domènec Espriu ◽

Albert Renau

Keyword(s):

Magnetic Field ◽

Dark Matter ◽

Galactic Halo ◽

Local Density ◽

Polarization Plane ◽

Strong Magnetic Fields ◽

Two Photon ◽

Main Effect ◽

Optical Table ◽

The Magnetic Field

In this work, we analyze the propagation of photons in an environment where a strong magnetic field (perpendicular to the photon momenta) coexists with an oscillating cold axion background with the characteristics expected from dark matter in the galactic halo. Qualitatively, the main effect of the combined background is to produce a three-way mixing among the two photon polarizations and the axion. It is interesting to note that in spite of the extremely weak interaction of photons with the cold axion background, its effects compete with those coming from the magnetic field in some regions of the parameter space. We determine (with one plausible simplification) the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments.

Download Full-text

Dynamic behavior of a nematic liquid crystal mixed with CoFe2O4 ferromagnetic nanoparticles in a magnetic field

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.246 ◽

2017 ◽

Vol 8 ◽

pp. 2467-2473 ◽

Cited By ~ 2

Author(s):

Emil Petrescu ◽

Cristina Cirtoaje ◽

Cristina Stan

Keyword(s):

Magnetic Field ◽

Liquid Crystal ◽

Dynamic Behavior ◽

Small Deviation ◽

Large Size ◽

Polarized Microscopy ◽

Nematic Director ◽

Small Distortion ◽

The Magnetic Field ◽

Microscopy Images

The dynamic behavior of a mixture of 4-cyano-4′-pentylbiphenyl (5CB) with 1% CoFe2O4 nanoparticles was analyzed. Experimental data indicate a high stability of the nematic director in the mixture compared to a reference 5CB sample in the magnetic field. The ferrite nanoparticles agglomerate forming long chains as observed in polarized microscopy images. These chains have a very high influence on the magneto-optic effect of the cell. When the magnetic field is applied on the mixture, the chains tend to align with the field direction but, due to their large size, they remain oriented obliquely between the support plates. Thus, the nematic molecules anchored on their surface can not reorient with the field and only a small distortion angle of the liquid crystal molecular director is observed. A comparison with a previously developed theoretical model confirms this small deviation.

Download Full-text

Optical Rotation Approach to Search for the Electric Dipole Moment of the Electron

Atoms ◽

10.3390/atoms7020056 ◽

2019 ◽

Vol 7 (2) ◽

pp. 56 ◽

Cited By ~ 2

Author(s):

Dmitry V. Chubukov ◽

Leonid V. Skripnikov ◽

Vasily N. Kutuzov ◽

Sergey D. Chekhovskoi ◽

Leonti N. Labzowsky

Keyword(s):

Dipole Moment ◽

Electric Dipole Moment ◽

Electric Dipole ◽

Faraday Effect ◽

Optical Rotation ◽

Polarization Plane ◽

Light Polarization ◽

Theoretical Simulation ◽

Electron Electric Dipole Moment ◽

Light Polarization Plane

The P , T -odd Faraday effect (i.e., rotation of the polarization plane of light propagating through a medium in presence of the external electric field due to P , T symmetry violating interactions) is considered for several atomic species: Ra, Pb, Tl, Hg, Cs, and Xe. Corresponding theoretical simulation of P , T -odd Faraday experiment, with already achieved intracavity absorption spectroscopy characteristics and parameters, is performed. The results show that the magnetic dipole transitions in the Tl and Pb atoms as well as the electric dipole transitions in the Ra, Hg and Cs atoms are favorable for the observation of the P , T -odd Faraday optical rotation. The estimation of the rotation angle of the light polarization plane demonstrates that recently existing boundaries for the electron electric dipole moment can be improved by one-two orders of magnitude.

Download Full-text

Numerical investigation of influence of ionic space charge and flexoelectric polarization on measurements of elastic constants in nematic liquid crystals

Opto-Electronics Review ◽

10.2478/s11772-008-0072-6 ◽

2009 ◽

Vol 17 (2) ◽

Cited By ~ 1

Author(s):

M. Buczkowska ◽

G. Derfel ◽

M. Konowalski

Keyword(s):

Magnetic Field ◽

Liquid Crystal ◽

Liquid Crystals ◽

External Magnetic Field ◽

Space Charge ◽

Elastic Constants ◽

High Concentration ◽

Light Passing ◽

The Magnetic Field

AbstractDeformations of nematic layers caused by magnetic field allow determination of the elastic constants of liquid crystal. In this paper, we simulated numerically the deformations of planar and homeotropic nematic layers. The flexoelectric properties of the nematic and presence of ions were taken into account. Our aim was to show the influence of flexoelectricity on the results of the real measurement of the elastic constants k33 and k11. In these simulations, we calculated the optical phase difference ΔΦ between the ordinary and extraordinary rays of light passing through the layer placed between crossed polarizers as a function of the magnetic field induction B. One of the elastic constants can be calculated from the magnetic field threshold for deformation. The ratio k33/k11 can be found by means of fitting theoretical ΔΦ(B) dependence to the experimental results. The calculations reveal that the flexoelectric properties influence the deformations induced by the external magnetic field. In the case of highly pure samples, this may lead to false results of measurement of the elastic constants ratio k33/k11. This influence can be reduced if the nematic material contains ions of sufficiently high concentration. These results show that the flexoelectric properties may play an important role, especially in well purified samples.

Download Full-text