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Journal of Radio Electronics Online scientific journal · eISSN 1684-1719
2021, № 1 · NONLINEAR WAVE DYNAMICS IN RADIO ELECTRONICS

Computer simulation of the pulse-periodic electric field effect on the 2D director orientation of nematic liquid crystal. Experimental research of multimode nematic liquid crystal waveguides

A.S. Ayriyan1,2, E.A. Ayrjan1,3, A.A. Egorov4,5

1 Joint Institute for Nuclear Research, Dubna, Russia
2 A.I. Alikhanyan National Science Laboratory, Erevan, Armenia
3 Dubna State University, Dubna, Russia
4 Moscow A.S. Popov Scientific-Technical Society of Radio Engineering, Electronics and Communications, Moscow, Russia
5 A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia
Full text (PDF) DOI: 10.30898/1684-1719.2021.1.8 UDC 535.13: 535.326: 535.36: 621.37 EDN YBSKHL

Abstract

In this paper, we numerically investigate a two-dimensional differential equation describing the motion of a director of a nematic liquid crystal for the case of an alternating external electric field. The presence of the previously discovered accumulation effect has been confirmed by numerical modeling. A comparison is made with the case of a constant electric field, and also a qualitative comparison with an experiment is given. Incomplete agreement with experimental data indicates the need for further research. However, it should be noted that the constructed mathematical model of the phenomenon allows at this stage to obtain estimates that are sufficiently acceptable for experiment and correctly predict the dynamics of processes in liquid crystals. An analysis of the features of the propagation of quasi-waveguide modes in a liquid crystal waveguide showed that, in the case of dynamic processes, such effects as power exchange between coupled modes, leakage of modes, re-emission of modes into modes of a different order, etc., can be observed. The programs for numerical solution and computer modeling of two-dimensional parabolic partial differential equation were developed both in FORTRAN and C/C++. The results obtained are important for further investigation of dynamic processes inside non-stationary liquid crystal layers, both from a theoretical point of view for understanding kinetic processes in liquid crystals and from a practical point of view when organizing and conducting different experimental research.

  • liquid crystal
  • director
  • 2D fluctuations
  • irregularities
  • boundary-value problem
  • optofluidics
  • waveguide
  • laser radiation
  • numerical simulation
Аннотация (на русском)

Компьютерное моделирование влияния импульсно-периодического электрического поля на двумерную ориентацию нематического жидкого кристалла. Экспериментальное исследование многомодовых нематических жидкокристаллических волноводов

В настоящей работе численно исследовано двумерное дифференциальное уравнение, описывающее движение директора нематического жидкого кристалла для случая переменного внешнего электрического поля. Численным моделированием подтверждено наличие обнаруженного ранее эффекта накопления. Проведено сравнение со случаем постоянного электрического поля, а также дано качественное сравнение с экспериментом. Неполное соответствие экспериментальным данным указывает на необходимость дальнейших исследований. Однако следует отметить, что построенная математическая модель явления позволяет на данном этапе получать достаточно приемлемые для эксперимента оценки и правильно предсказывать динамику процессов в жидких кристаллах. Анализ особенностей распространения квази-волноводных мод в жидкокристаллическом волноводе показал, что в случае динамических процессов могут наблюдаться такие эффекты, как обмен мощностью между связанными модами, вытекание мод, переизлучение мод в моды другого порядка и др. Программы для численного решения и компьютерного моделирования двумерного параболического дифференциального уравнения в частных производных были разработаны как на ФОРТРАНЕ, так и на C/C++. Полученные результаты важны для дальнейшего исследования динамических процессов внутри нестационарных жидкокристаллических слоев, как с теоретической точки зрения для понимания кинетических процессов в жидких кристаллах, так и с практической, - при организации и проведении экспериментальных исследований.

For citation

Ayriyan A.S., Ayrjan E.A., Egorov A.A. Computer simulation of the pulse-periodic electric field effect on the 2D director orientation of nematic liquid crystal. Experimental research of multimode nematic liquid crystal waveguides // Journal of Radio Electronics. – 2021. – No. 1. https://doi.org/10.30898/1684-1719.2021.1.8

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