Accelerating the Cholesteric Helix Restoring by a Dual Frequency Compound

Abstract

We report the creation and the use of dual frequency cholesteric liquid crystal mixtures for the dynamic electrical unwinding and forced (accelerated) restoring of their molecular helix. The use of a cholesteric in a mixture with a dual frequency nematic shifts the resonant wavelength to the near infrared area. We use polarimetric transmission measurements (out of resonance) to check the effective birefringence of the cell as well as the resonant reflection (at near infra red) to characterize the dynamics of unwinding and restoring processes. The restoring process is accelerated almost by an order of magnitude for quite moderate voltages used.

Keywords:

• Cholesteric liquid crystals
• dual frequency liquid crystal
• electrooptic switch
• frequency control
• liquid crystals
• polarimetry
• resonant reflection

Acknowledgment

We thank the financial support of Canadian Institute for Photonic Innovations (CIPI), Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT) and Natural Sciences and Engineering Research Council of Canada (NSERC).