Liquid crystals over the last two decades have been successfully used to infiltrate fiber-optic and photonic structures initially including hollow-core fibers and recently micro-structured photonic crystal fibers (PCFs). As a result photonic liquid crystal fibers (PLCFs) have been created as a new type of micro-structured fibers that benefit from a merge of “passive” PCF host structures with “active” LC guest materials and are responsible for diversity of new and uncommon spectral, propagation, and polarization properties. This combination has simultaneously boosted research activities in both fields of Liquid Crystals Photonics and Fiber Optics by demonstrating that optical fibers can be more “special” than previously thought. Simultaneously, photonic liquid crystal fibers create a new class of fiber-optic devices that utilize unique properties of the photonic crystal fibers and tunable properties of LCs. Compared to „classical” photonic crystal fibers, PLCFs can demonstrate greatly improved control over their optical properties. The paper discusses the latest advances in this field comprising PLCFs that are based on nanoparticles-doped LCs. Doping of LCs with nanoparticles has recently become a common method of improving their optical, magnetic, electrical, and physical properties. Such a combination of nanoparticles-based liquid crystals and photonic crystal fibers can be considered as a next milestone in developing a new class of fiber-based optofluidic systems.
The direction of liquid crystal (LC) arrangement can be changed by different techniques. Photo-alignment method
appears to be potentially the best technique to use in the case of micro–capillaries. Developing the photo-alignment
method of liquid crystal molecules in silica micro–capillaries allowed to work on obtaining periodic orientation. The
usage of amplitude masks in the irradiation allows to obtain a periodic alignment of molecules variable within a single
sample. In this paper, the experimental results of the periodic orientations achieved are presented.
In this paper we present the theoretical and experimental analysis of the micro-electrodes system for the for dynamic change of the electric field direction. The system consists of four micro-electrodes introduced into the micro-holes and one rectangular air hole in the center and can applied for electric field sensing with polymer-based micro-structured optical fibers infiltrated with liquid crystals.
Photonic liquid crystal fibers allow for dynamic modification of their guiding and polarization properties. In particular it is possible to dynamically tune phase delay between two orthogonal polarization of the guided mode. In this work an index-guiding photonic liquid crystal fiber with highly tunable retardation, reaching value of 15λ (or 30π in terms of phase difference) is presented. Electric tuning with two sets of electrodes is also discussed and demonstrated proving that photonic liquid crystal fibers can be utilized as a all-in-fiber polarization controllers.
Properties of photonic crystal fibers (PCFs) filled with nematic liquid crystals (LC) can be easily tuned by using an
external electric field. In this work we focus on electrical tuning of index-guiding photonic liquid crystal fibers (PLCF)
based on fibers made from multi-component glasses with an enhanced value of the refractive index. The impact of an
electric field on light propagation in index guiding PLCFs has been carefully studied and the effective tuning of phase
birefringence has been observed experimentally. The dependence of time response on the modulation level will be
presented. In the end we will show polarization controller made with two pair of electrodes.
In great majority of the previous works devoted to photonic liquid crystal fibers (PLCFs) a photonic band-gap
propagation was investigated, since silica glass fibers' refractive index is lower than refractive indices of the most of
liquid crystals. In this work we focus on the electrical tuning of the index-guiding PLCFs based on host-fibers made from
multi-component glasses with enhanced value of refractive index. Impact of the electric field on the light propagation in
index-guiding PLCFs has been carefully studied and effective tuning of the phase birefringence, attenuation and
polarization dependent losses has been observed experimentally.