Influence of temperature and electrical fields on propagation properties of photonic liquid-crystal fibres

Abstract

The paper reports temperature and external electrical field effects on propagation properties of a photonic liquid-crystal fibre composed of a solid-core photonic crystal fibre filled either with a prototype nematic liquid crystal characterized by extremely low (of the order of ∼0.05) material birefringence or with a typical nematic pentylo-cyano-biphenyl, PCB (birefringence of the order of ∼0.2). The nematic liquid crystal was introduced into the micro holes of the photonic crystal fibre by the capillary effect. Depending on the liquid crystal material introduced into the micro holes and due to anisotropic properties of the photonic liquid-crystal fibre, switching between different guiding mechanisms controlled by temperature and an external electric field has been demonstrated. This creates great potential in fibre optic sensing and optical processing application.

Tunable filter based on two cascaded photonic liquid crystal fibers

“…It was very important to obtain two PLCFs with almost identical signals. In our previous works [15,17] we noticed that the 1023 PCF with the 1550 LC mixture gives highly repeatable wide band gaps with repeatable tuning.…”

Numerical Investigation of Nanostructured Silica PCFs for Sensing Applications

“…Liquid crystal materials infused into the cladding holes creates a PBG (photonic bandgap) effect, restricting the modes within the core region rather than leaking, facilitating a stronger sensing signal. 16 NIR wavelengths of the optical spectrum are of particular interest for fiber-optic sensing applications due to their improved sensitivity and accuracy compared to other spectral regions. The NIR bands have shown high sensitivities to methane gas sensing, which is of great interest in many industrial and safety applications.…”

Tunability of discrete diffraction in photonic liquid crystal fibres

“…Propagation properties of PCFs can be dynamically changed (including switching between different guiding mechanisms) by introducing gaseous, liquid or solid media into the air−channels [1,[11][12][13][14][15][16][17]. This simple idea has been found to be very useful while broadening the applicability of PCFs.…”

“…Specifically, the concept of using liquid crystals (LCs), resulting thus in a new type of optical fibres, has gained significant amount of the scientific attention. These particular photonic structures are often referred to as pho− tonic liquid crystal fibres (PLCFs) [12][13], liquid crys− tal−photonic crystal fibres (LC−PCFs) [14], or liquid crys− tal−photonic bandgap fibres [15]. LCs are anisotropic, and, in most cases, their (averaged) refractive indices are higher than that of silica (glass).…”

“…Furthermore, the refractive indices of LCs can also be engineered and/or dynamically adjusted [18]. High tunability of optical properties of PLCFs [mani− fested, e.g., by (i) tuning and/or switching of the guiding mechanisms or (ii) changes in discrete propagation], achie− ved by applying external factors like temperature, strain, pressure, electric or/and magnetic fields, as well as by the light−beam itself (e.g., when nonlinear effects in LCs are considered), brings various potential applications to the field of fibre optics [12][13][14][15][16][17].…”