Abstract
Heliconical cholesteric liquid crystals are expected to be more sensitive to torque induced by light field since their structure allows both bend and twist in molecular orientations, differently from the conventional cholesterics in which only twist deformation is involved, requiring much higher fields. We report here a demonstration of tuning the helical pitch in heliconical cholesterics induced by an optical torque. Experimental observations are in agreement with expectations of the classical theory extended to include the effect of the optical field. A dual control of the helical pitch is achieved including both the low-frequency electric field applied along the helix axis and the optical field orthogonal to it.
Highlights
The effects of applied fields on the helical structure of cholesteric liquid crystals have been a subject of extended investigation since the very beginning of research on liquid crystals
When the applied field is parallel to the helix axis the perturbation involves both bend and twist deformations, the resulting effect depends on the ratio of the corresponding elastic constants K3 and K2, k = K3/K2
Concerning the effects of the optical field, just after the discovery of the giant optical nonlinearity (GON) due to optical reorientation in nematics, the possibility to get an all-optical control of the Bragg reflection of cholesterics was considered by using a light beam to induce an optical torque on the molecular director
Summary
The effects of applied fields on the helical structure of cholesteric liquid crystals have been a subject of extended investigation since the very beginning of research on liquid crystals. Concerning the effects of the optical field, just after the discovery of the giant optical nonlinearity (GON) due to optical reorientation in nematics, the possibility to get an all-optical control of the Bragg reflection of cholesterics was considered by using a light beam to induce an optical torque on the molecular director.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
