Optical diffraction by using electrically-controlled spatially patterned nematic pentylcyanobiphenyl films under static electric field

ABSTRACT

Diffractive electro-optics of electrically-induced spatially periodic texture patterns (namely, wide-formed stationary parallel stripes) in planarly-aligned films of the nematic liquid crystal 4-n-pentyl-4′-cyanobiphenyl (5CB) is examined under static electric field in view of its practical application. The longitudinal textural domains electrically-induced with well defined threshold and spatial period have flexo-dielectric nature and differ from the usual flexoelectric stripe distortion, as well as from the electroconvective domains of frequency-dependent morphology. The low-voltage-controlled grating effect through the flexo-dielectric domains can be useful for nematic diffractive optics.

KEYWORDS:

• Nematics liquid crystals
• pentylcyanobiphenyls
• electro-optics
• optical phase grating
• spatially-periodic patterned array
• coherent light diffraction

Acknowledgments

INERA EU project Research Potential (FP7-316309-REGPOT-2012-2013-1) is acknowledged, as well as the funding by the Ministry of Education and Science and National Science Fund of Bulgaria within the framework of research projects DFNI-TO2/10 and DFNI-TO2/18. The authors are extremely grateful to Academician Alexander Petrov and Assoc. Prof. DSc. Hristo Hinov from the Institute of Solid State Physics “Acad. Georgi Nadjakov”, Bulgarian Academy of Sciences, for their valuable comments and suggestions, and for the helpful discussions.