Enhancement of electro-optical response of photonic crystal fibers infiltrated with ferroelectric liquid crystal doped with titanium dioxide nanoparticles.

Light propagation has been studied in photonic crystal fibers (PCFs) doped with W212 ferroelectric liquid crystal (FLC) composites with titanium dioxide nanoparticles (TiO2 NPs) of low concentrations between 0.2 and 1 wt. % in the FLC matrix. Optical microscopy observations indicated a slight increase of transition temperature to the isotropic phase by ∼1-2°C compared to the undoped FLC sample, and the TiO2 admixture was found to decrease free ionic charge impurities in the FLC, thus improving its electro-optical parameters. The switching time measurements in the PLCFs clearly indicate that TiO2 NPs reduce switching times for low electric field intensity, even by 32% compared to the undoped PLCF.

Breast phantom for comparison X-ray and polarimetric optical tomography imaging.

Breast phantom made as combination of paraffin and INTRALIPID™ was tested by use of X-ray classical computed tomography and polarimetric optical tomography. The INTRALIPID™ is a liquid commonly used for simulation breast tissues optical properties but it is useless as X-ray phantom. During our tests we have observed that X-ray tomography allows to recognize a proper placement of INTRALIPID™ inclusions inside paraffin medium but we cannot distinguish density of INTRALIPID™ within each inclusions. On the other hand the polarimetric optical tomography allows to distinguish density of INTRALIPID™ (0%, 10%, 20%) in inclusions but with relatively low accuracy of their placement.

Hydrostatic pressure effects on mode propagation in highly birefringent two-mode bow-tie fibers.

An experimental study on the effects of high hydrostatic pressure of as much as 100 MPa on mode propagation in a highly birefringent two-mode bow-tie fiber is presented. Hydrostatic pressure is found to produce a large phase shift between both orthogonal polarizations in fundamental and second-order modes and also between the two lowest-order spatial modes in the highly birefringent two-mode bow-tie fiber. The pressure-induced effects are expressed in terms of birefringence changes and pressure phase sensitivity, both described by the experimental parameter T(p). The results indicate that pressure phase sensitivity between the two spatial modes, 1.3 rad/MPa-m, is approximately one order lower than for polarization modes.

Influence of high hydrostatic pressure on beat length in highly birefringent single-mode bow tie fibers.

New experimental studies on the effects of high hydrostatic pressure on highly birefringent optical fibers are presented. Using Rayleigh scattering, the effect of beat length modification in highly birefringent singlemode bow tie fibers under high pressure up to 100 MPa was investigated. The results indicate that the beat length decreases with pressure, with the mean coefficient of 1/L(B0)|dL(B)/dp| = 0.15%/MPa. A similar decrease of beat length was observed when uniaxial longitudinal stress was applied to the bow tie fiber. A more developed semiphenomenological interpretation of these experimental results is also presented in the paper.