We report the first experimental realization of spatial soliton formation by the Gaussian beam at 632.8 nm in the azobenzene liquid crystal (LC) layer with planar orientation of LC director. By appropriate anti-parallel rubbing of alignment layers on the upper and lower substrates of the cell LC molecules were oriented along the glass substrates nearly perpendicular to the input window of the cell with a small pre-tilt angle of ~2.60 relative to the beam propagation Z direction. The strong self-focusing effect and soliton formation for laser beam with vertical Y-polarization and beam diffraction for horizontal X-polarization have been observed in the absence of an external electric field. The physical model is considered which implies that the interaction of azobenzene molecules with a laser field is much stronger due to a larger coefficient of orientation nonlinearity compared to other LCs, as well as they are not rigidly anchored to the cell boundary. Thus the molecule alignment can be readily varied by a low-power laser field even for a small pre-tilt angle of molecules which leads to the refractive index change and beam self-focusing regime. The numerical integration of the propagation equation for spatial solitons describes the experimental data very well.
In the present work the X-ray optical anisotropy of 5CB type liquid crystals has been investigated based on the method
of X-ray interferometry. In this way Moire fringes have been obtained both in the absence and presence of specimens
with different orientations of optical axes. The relative displacement of Moire fringes enabled us to observe and
immediately ascertain the presence of X-ray optical anisotropy, to measure the values of refractive indices no and ne for
this specimen (no is the refractive index for radiation with polarization normal to the principal plain, ne is that for
radiation with polarization in the principal plain parallel to the optical axis). X-ray optical anisotropy of 5CB type liquid
crystal was observed using the proposed method and values of refractive indices no and ne for this specimen were
measured. It was found out that 5CB type nematic liquid crystal was X-ray anisotropic optically positive medium.
We investigate spectral peculiarities of multilayer system, consisting of two identical CLC layers and
a Rhodamine 6G doped polymethyl metacrylate thin film sandwiched between them. We measure
transmission and reflection spectra of the system. A small mismatch between Selective reflection band and
corresponding dip in transmission spectrum is observed. Also we investigate luminescence spectrum of this
system at pulsed and CW mode pumping at various temperatures. The results show that maximal intensity of
luminescence spectrum at constant pumping power is observed at 18°C and the weakest luminescence is
observed at 20°C, the luminescence spectra at higher and lower temperatures are “confined” between these
two spectral curves.
In this work we have experimentally investigated optical properties of multilayered structure, consisting of two
right handed Cholesteric Liquid Crystal layers with the same pitch and Rhodamine 6G (R6G) doped polymethyl
metacrylate (PMMA) thin film sandwiched between them. Particularly transmission spectrum dependence on
temperature is studied. The 10 nm of CLC selective reflection band tuning is achieved. The photoluminescence of R6G