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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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Bistable light-driven π phase switching using a twisted nematic liquid crystal film
Optics Express
|June 13, 2014
Summary
A novel light-activated optical phase switch utilizes the conversion between left-handed and right-handed liquid crystals. This handedness change in the twisted nematic film shifts the optical phase by π.
Area of Science:
- Materials Science
- Optoelectronics
- Liquid Crystal Physics
Background:
- Twisted nematic liquid crystals (LCs) are crucial for optical devices.
- Controlling the handedness of LC phases is key to advanced optical functionalities.
- Photo-responsive LCs offer tunable optical properties.
Purpose of the Study:
- To develop a light-activated optical phase switch.
- To investigate the mechanism of handedness inversion in twisted nematic films.
- To explore the role of chiral dopants and azobenzene chromophores.
Main Methods:
- Fabrication of a twisted nematic liquid crystal film with chiral dopants.
- Utilizing azobenzene chromophores for photo-responsiveness.
- Theoretical modeling and experimental analysis of optical phase shifts.
Main Results:
- Demonstrated a light-activated switch based on LC handedness conversion.
- Observed an optical phase shift of π due to handedness inversion.
- Identified the competition between chiral dopants as the determinant of film handedness.
- Attributed photo-responsibility and bistability to azobenzene chromophores.
Conclusions:
- A functional light-activated optical phase switch was successfully developed.
- The study elucidates the fundamental principles governing LC handedness control.
- This work paves the way for new photo-switchable optical devices.
