Light Propagation in Confined Nematic Liquid Crystals and Device Applications

Abstract

Liquid crystals are interesting linear and nonlinear optical materials used to make a wide variety of devices beyond flat panel displays. Liquid crystalline materials can be used either as core or as cladding of switchable/reconfigurable waveguides with either an electrical or an optical control or both. In this paper, materials and main device structures of liquid crystals confined in different waveguide geometries are presented using different substrate materials, such as silicon, soda lime or borosilicate glass and polydimethylsiloxane. Modelling of the behaviour of liquid crystal nanometric molecular reorientation and related refractive index distribution under both low-frequency electric and intense optical fields is reported considering optical anisotropy of liquid crystals. A few examples of integrated optic devices based on waveguides using liquid crystalline materials as core for optical switching and filtering are reviewed. Reported results indicate that low-power control signals represent a significant feature of photonic devices based on light propagation in liquid crystals, with performance, which are competitive with analogous integrated optic devices based on other materials for optical communications and optical sensing systems.

Properties of liquid-crystal wave-guiding structures

“…A brief analysis of scientific publications devoted to the development of research in the field of liquid crystals 1,2 and their applications in integrated optics 3–18 is made. The most interesting, from our point of view, works, both for science and for practice, are marked.…”

“…For a more detailed acquaintance with the latest achievements in this rapidly developing branch of science and technology, we strongly recommend that you familiarize yourself with the publications. 3–18…”

“…In a recently published review 18 authors pay attention to a variety of different liquid crystal linear and nonlinear optical materials that used to make a wide variety of devices. They discussed different materials and main device structures of liquid crystals confined in different waveguide geometries.…”

“…More over these devices has performance, which are competitive with analogous integrated optic devices based on other materials for optical communications and optical sensing systems. 18 Undoubtedly, this review allows us to see the development of this actively developing field of research, starting from the stage of choosing promising liquid crystals and ending with a description of a number of specific liquid crystal devices.…”

“…The list of required literature on this topic and related areas can be easily expanded by citations in the indicated publications. 1–33 From this point of view, of undoubted interest is, for example, the review. 18 At the same time, it should be emphasized that it is really possible to give a detailed analysis of the development of the situation in the actively developing field of science and technology only in a special review.…”