Katarzyna Szaniawska

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

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.

Polarization Optics of Microstructured Liquid Crystal Fibers

The present paper discusses polarization phenomena occurring in microstructrured liquid crystal fibers and in particular solid-core photonic crystal fibers infiltrated with liquid crystals. We report on the latest experimental polarization characteristics of microstructured photonic crystal fibers filled with prototype nematic liquid crystal guest materials characterized by either extremely low (of the order ∼ 0.05) or medium (of the order ∼ 0.2) material birefringence. Due to anisotropic properties of the microstructrured liquid crystal fibers switching between different guiding mechanisms as well as electrically and temperature-induced tuning of light propagation have been demonstrated. These preliminary results hold great potential for both fiber-optic sensing and in-fiber polarization mode dispersion control and compensation.

Temperature tuning in photonic liquid crystal fibers

The paper presents our latest experimental results on influence of temperature on the propagation properties of photonic liquid crystal fibers. We used solid-core photonic crystal fibers filled either with a low-birefringence prototype 1550 liquid crystal mixture or with PCB. It appeared that direction of temperature tuning in PLCFs is strongly dependent on thermal characteristics of both refractive indices.

Influence of electrical field on light propagation in microstructured liquid crystal fibers.

Microstructured optical fibers have ability to change their optical properties through inserting different materials into their holes. Filling the microstructured fibers with liquid crystals opens up a possibility of dynamic switching between different guiding mechanisms. In this paper we present the influence of electrical field on propagation properties of microstructured photonic crystal fibers filled with either low or highly birefringent nematic liquid crystals. Depending on the liquid crystal material introduced into the micro holes different propagation mechanism controlled by external electric field have been observed. This creates great potential in fiber optic sensing and optical processing application.

Propagation effects in photonic liquid crystal fibers

Propagation effects in photonic liquid crystal fiber (PLCF) microstructures, composed of photonic crystal fibers (PCFs) filled with nematic liquid crystals (NLCs), are investigated. Due to the introduction of NLCs characterized by both low and high material birefringence into the cladding air holes, photonic bandgap guiding has been observed.

Propagation effects in a photonic crystal fiber filled with a low-birefringence liquid crystal

In this paper propagation properties in photonic crystal fibers (PCFs) filled with extremely low-birefringence nematic liquid crystal (LC) mixtures have been investigated. The low-birefringence nematic LC compositions included multicomponents esters mixtures and were characterized by extremely low ordinary no = 1.46-1.45 and extraordinary ne = 1.478-1.505 refractive indices at room temperature. Due to reorientation possibilities of nematic molecules within the fiber holes, propagation properties of the obtained photonic liquid crystal fibers could be easily modified.

Spectral and polarization properties of microstructured liquid crystal fibers

Spectral and polarization properties of microstructured photonic crystal fibers filled with nematic liquid crystals characterized by either extremely low (of the order ~ 0.05) or higher (of the order ~ 0.3) material birefringence have been investigated. The photonic crystal fiber used as a host material was manufactured in Lublin, Poland and the nematic liquid crystals were introduced into the micro holes of the photonic crystal fiber by the capillary effect. Due to anisotropic properties of the obtained microstructured photonic liquid-crystal fiber, switching between different guiding mechanisms as well as novel spectral and polarization phenomena have been observed.

Tunable properties of light propagation in photonic liquid crystal fibers

Tunable properties of light propagation in photonic crystal fibers filled with liquid crystals, called photonic liquid crystal fibers (PLCFs) are presented. The propagation properties of PLCFs strongly depend on contrast between refractive indices of the solid core (pure silica glass) and liquid crystals (LCs) filing the holes of the fiber. Due to relatively strong thermo-optical effect, we can change the refractive index of the LC by changing its temperature. Numerical analysis of light propagation in PLCF, based on two simulation methods, such as finite difference (FD) and multipole method (MM) is presented. The numerical results obtained are in good agreement with our earlier experimental results presented elsewhere [1].

Application of photoelastic tomography to measurement of refractive indices in optical anisotropic microelements

In the paper we present method for three-dimensional measurement of birefringence distribution in anisotropic objects. The tool, which we used is combination of classic polariscopy with tomographic reconstruction method. Tomographic reconstruction is performed using the filtered backpojection algorithm. The results of measurement of glass capillary infilled with licquid crystal are presented together with the results of numerical simulation of measurement process. Simulations include polarized light propagation performed by means of finite difference time domain method combined with Jones calculus. The numerical simulations are performed for various birefringence values and allow for determination of relative errors of birefringence distribution. Additionally the absolute refractive indices are determined experimentally through the measurement of capillary with polarization sensitive microinterferometric tomography.

Analysis of light propagation mechanisms in photonic liquid crystal fibers

The paper reports numerical analysis of light propagation in a photonic crystal fiber filled with a nematic liquid crystal. Such fiber is not only an advanced anisotropic structure, but also can experience a change in its light propagation mechanism: from index guiding to the photonic band gap mechanism. Both of these mechanisms can be extensively tuned due to variations of liquid crystals and silica glass refractive indices differences. The obtained numerical simulations are confirmed by experimental results.