Accession Number : ADP007586

Title :   Measurement of High Frequency Electro-Optic Coefficient in Ferroelectric Liquid Crystal Materials,

Corporate Author : COLORADO UNIV AT BOULDER DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s) : Liu, J. Y. ; Robinson, M. G. ; Johnson, K. M. ; Doroski, D.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : Ferroelectric liquid crystals (FLC's) form the thermodynamically stable Smectic C* liquid crystalline phase that is non-centrosymmetric and has macroscopic polar order. The symmetry (C sub 2) implies that FLC materials can exhibit second order nonlinear properties such as the linear electro-optic(EO) effect and second harmonic generation (SHG). In most FLC's designed for optical modulation applications these nonlinearities are small, but in principle could be made large by specifically synthesizing liquid crystal molecules which self-assemble in such a way that functional groups with large microscopic hyperpolarizabilities, Beta's, are oriented along the polar axis. By adopting this approach to produce second order nonlinear material, the problems associated with processing organic single crystals are avoided. Furthermore, the flexibility of the liquid crystal technology can be used to design materials with specific refractive indices for phase matching purposes and waveguide design. Waveguides in this material system are particularly interesting as they allow a significant increase in optical propagation length with high electric field generation capability; both important attributes for nonlinear optical phenomena. Preliminary work has already been carried out on waveguide structures whose possibilities are numerous owing to the ability to successfully align FLC's on many different substrates (including Si).

Descriptors :   *LIQUID CRYSTALS, *FERROELECTRIC MATERIALS, *ELECTROOPTICS, *KERR MAGNETOOPTICAL EFFECT, ELECTRIC FIELDS, HARMONICS, LENGTH, MATCHING, MODULATION, MOLECULES, OPTICAL PHENOMENA, PHASE, PROCESSING, PROPAGATION, SINGLE CRYSTALS, STRUCTURES, SYMMETRY, WAVEGUIDES, SYMPOSIA.

Subject Categories : Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE