標題: Origins of Kerr Phase and Orientational Phase in Polymer-Dispersed Liquid Crystal
作者: Chang, Chia-Ming
Lin, Yi-Hsin
Reshetnyak, Victor
Park, Chui Ho
Manda, Ramesh
Lee, Seung Hee
光電工程學系
Department of Photonics
關鍵字: Liquid crystals;Kerr effect;Optoelectronics;Polymer dispersed liquid crystal;Optical phase modulation
公開日期: 1-Jan-2017
摘要: The anisotropic properties of nematic liquid crystals result in polarization dependency which leads to requirement of at least a polarizer in liquid crystal photonic devices. To develop polarizer free phase modulation, Kerr effect is one of the path. The phase modulation in polymer dispersed liquid crystals (PDLCs) is shown to have two parts: Kerr phase, which is the optical phase modulation linearly proportional to a square of electric field, and orientational phase. However, many puzzles are still under investigation: the origins of Kerr phase, the relation between Kerr phase and orientational phase, and how two-steps of electro-optical (EO) response relates to Kerr phase and orientational phase. We investigated the origins of Kerr phase and orientational phase in PDLC and their connection to two-step EO response. In our study, the Kerr phase is a result of LC orientation in the center of LC droplets. The orientational phase attribute to orientation of LC molecules near LC-polymer interfaces. The two phase in PDLC samples are adjustable depending on droplet size. We also found that two-steps EO response existing in small droplet (<333 nm) is related to Kerr phase and orientational phase. A modified PDLC model related to the Kerr phase and orientational phase is also proposed. Besides the conventional features of PDLC, such as polarization independent optical phase shift and response time independent of cell gap, we believe the Kerr phase and orientational phase with different response times (similar to msec) in PDLC pave a way for designing versatile photonic devices with pure optical phase modulation.
URI: http://dx.doi.org/10.1117/12.2275579
http://hdl.handle.net/11536/146886
ISSN: 0277-786X
DOI: 10.1117/12.2275579
期刊: LIQUID CRYSTALS XXI
Volume: 10361
Appears in Collections:Conferences Paper