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Prof. Miroslaw Karpierz - Faculty of Physics, Warsaw University of Technology

All optical beam steering in chiral nematic liquid crystals

Time: Thu 2014-11-06 09.00 - 11.00

Location: FA32

Participating: Miroslaw Karpierz

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Titel: All optical beam steering in chiral nematic liquid crystals

Abstract:

Nematic liquid crystals (NLCs) are widely used optoelectronic materials with many unique properties resulting from their anisotropy and facility of changing their orientation by external fields. It led to many essential applications like displays or spatial light modulators. Chiral nematic liquid crystals (ChNLC) creates layered structures with periodically changed refractive index. Such a structure can be treated as an array of a planar waveguides and depending on the refractive index variation the light can be guided in the individual waveguide or can be coupled between them. It results in dual diffraction, i.e. discrete and continuous diffraction existing simultaneously in two orthogonal planes.

For many years there are also interests in application of NLCs to nonlinear optics, where the reorientation of molecules by electric field of electromagnetic waves is a basis of reorientational nonlinearity. In NLCs and ChNLCs nonlinear effects like self-focusing, self-phase modulation, self-guiding, wave mixing, stimulated scattering and phase conjugation have been reported. Among them very prospective seem to be creation of optical spatial solitons governed by reorientational nonlinearity, called nematicons. Nematicons require very low power and have been previously observed in different geometries and configurations, showing the possibility of guiding signal beams and steering by external fields or other nematicons.

  1. Nematicons: spatial optical solitons in nematic liquid crystals, ed. By G. Assanto, Wiley, 2013
  2. G. Assanto, M. A. Karpierz, „Nematicons: self-localised beams in nematic liquid crystals”, Liq. Cryst. 36, 1366 (2009)
  3. U.A. Laudyn, M.A. Karpierz, „Nematicons deflection through interaction with disclination lines in chiral nematic liquid crystals,” Appl. Phys. Lett. 103 (2013)
Page responsible:Peter Unsbo
Belongs to: Department of Applied Physics
Last changed: Oct 29, 2014