Dancing vortices in a driven nematic liquid crystal cell: Theory and experiment

Area of Science:

• Optics and Photonics
• Soft Matter Physics
• Nonlinear Dynamics

Background:

• Optical vortices are generated by light beam interactions with helical defects in materials.
• Controlling these helical defects enables the development of tunable optical vortex beam sources.
• Matter vortices in liquid crystals offer a novel platform for studying complex dynamics.

Purpose of the Study:

• To investigate the dynamics of helical defects in nematic liquid crystals.
• To explore the creation and characteristics of matter vortices under external stimuli.
• To establish a theoretical framework for describing observed vortex behaviors.

Main Methods:

• Trapping helical defects using a magnetic ring within a nematic liquid crystal cell.
• Applying low-frequency voltage to induce and observe vortex dynamics.
• Experimentally mapping the parameter space for vortex observation.
• Developing an amplitude equation to model vortex dynamics.

Main Results:

• Observation of oscillatory rotating and beating matter vortices.
• Determination of the parameter region for vortex manifestation.
• Quantification of the amplitude decay of oscillatory vortices with inverse voltage frequency.
• Qualitative agreement between theoretical predictions and experimental results.

Conclusions:

• Helical defects in liquid crystals can be manipulated to form observable matter vortices.
• The dynamics of these matter vortices are voltage- and frequency-dependent.
• The proposed theoretical model provides a valid description of the observed vortex phenomena.