Liquid crystal alignment in cylindrical microcapillaries

Abstract

A variety of alignment configurations of liquid crystals (LCs) inside the glassy cylindrical capillaries is realized by using alignment materials providing different anchoring. The radial configuration with central disclination line is obtained for homeotropic boundary conditions. In turn, the axial, transversal and tilted alignment structures are realized by using materials for planar anchoring. The uniformity and controlling of the latter structures were provided by photoalignment method. This approach can be further used to control LC alignment in the photonic crystal fibers recognized as advanced elements for different optical devices.

Photo-alignment of liquid crystals in micro capillaries with point-by-point irradiation

“…They both create a thin layer within a micro hole of the fibre before filling it with a LC [15][16]. The layer can be com− posed of: polymers, azo−dyes [17][18] or different LCs [19][20].…”

Fabrication and characterization of Mach–Zehnder interferometer based on a hollow optical fiber filled with radial-aligned liquid crystal

“…Based on these photos, we can say that the PI alignment layer indeed makes the LC direc tors inside the HOF axial symmetrical and orientated verti cally near the capillary wall and along the capillary axis in the central area as schematically presented in figure 3(f). The nonradial LC alignment in the central area is caused by the line disclination 'escaped' along the axis of a cylindrical cap illary [20]. This configuration is known as escaped radial or splay arrangement.…”

Improving the electric field sensing capabilities of the long-period fiber grating coated with a liquid crystal layer

“…The next possible improvement involves pre-coating of the LPFG with a thin orientation layer for a LC e.g. by using a polyimide resin [22,23]. In addition, many of these materials possess high refractive indices.…”