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Nastishin Yu.A.,Institute of Physical Optics | Nastyshyn S.Yu.,Ivan Franko National University of Lviv
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

An integral Jones matrix for oblique light propagation through a deformed crystal is derived using the differential Jones matrix approach. We show that generally at oblique light propagation a crystal monotonically deformed along its normal should show both linear and circular birefringence, even without twist deformation. The capability of the approach is illustrated by the calculation of the integral extended Jones matrices for oblique light propagation through several deformed liquid crystal nematic cells. In particular, we predict that at oblique light propagation in certain directions the nontwisted hybrid nematic cell (in which the tilt angle of the optic axis with respect to the crystal plate normal smoothly varies through the thickness) shows optical activity, a phenomenon of spatial light dispersion akin to so-called weak optical activity in nonchiral polar solid crystals. © 2013 American Physical Society. Source

Padlyak B.,Institute of Physical Optics | Padlyak B.,University of Zielona Gora | Drzewiecki A.,University of Zielona Gora
Journal of Non-Crystalline Solids | Year: 2013

A series of borate glasses of high optical quality with CaB 4O7:Tb, LiCaBO3:Tb, CaB4O 7:Dy, and LiCaBO3:Dy compositions containing 0.5 and 1.0 mol% Tb2O3 and Dy2O3 impurity compounds were obtained from corresponding polycrystalline compounds using standard glass technology. By electron paramagnetic resonance (EPR) and optical spectroscopy it was shown that the Tb and Dy impurities are incorporated as Tb3 + (4f8, 7F6) and Dy 3 + (4f9, 6H15/2) ions in the Ca and Li(Ca) sites of CaB4O7 and LiCaBO3 glasses network, respectively. The luminescence excitation and emission spectra as well as luminescence kinetics of the Tb3 + and Dy3 + centres in the CaB4O7 and LiCaBO3 glasses have been investigated and analysed in comparison with obtained earlier results for Tb3 + and Dy3 + centres in the Li2B 4O7 glasses. All observed f-f transitions of the Tb 3 + and Dy3 + centres in the luminescence excitation and emission spectra have been identified. Luminescence kinetics show single exponential decay for Tb3 + and Dy3 + centres in the CaB4O7 and LiCaBO3 glass network. The lifetime values for the main emitting levels of the Tb3 + and Dy3 + centres in all investigated glasses were determined at room temperature and their dependencies on the basic glass compositions and impurity concentrations are discussed. The obtained results show that the CaB4O7 and LiCaBO3 glasses are promising luminescent materials, operating in green and yellow-blue spectral regions, when activated with Tb3 + and Dy3 + ions, respectively. © 2013 Elsevier B.V. Source

Fadeyeva T.A.,Taurida National University | Fadeyeva T.A.,Institute of Physical Optics
Ukrainian Journal of Physical Optics | Year: 2013

In the framework of paraxial approximation we consider evolution of a monochromatic Gaussian beam diffracted by a corner formed by three verges of the phase wedges of different types and the π -phase plate. We have found that the edges of the phase wedge generate macroscopic chains of identical optical vortices that disappear at the far field zone. At the same time, the π -phase plate can reproduce a very complex wave field whose structure depends on the scale of observation. At large scales there appear two π -cuts resembling broken edge dislocations with perpendicular directions. At small (some microns) scales two short vortex chains consisting of alternating-sign optical vortices are nucleated near the corner of the wedge. The analysis shows that the sizes of the chains decrease quickly when approaching the wedge surface. This enables us to assume that the π -phase plate can create so-called optical quarks in the evanescent waves of the edge field. Source

Skab I.,Institute of Physical Optics
Ukrainian Journal of Physical Optics | Year: 2012

The torsion method for measuring piezooptic coefficients π14 and π25 in the trigonal crystals belonging to the point symmetry groups 3 and 3 is described. The XY-distributions of the optical indicatrix orientation and the optical birefringence induced by the torsion stresses are analysed and evaluated quantitatively. It is shown that the spatial birefringence distribution in the sample subjected to torsion around the Z axis represents a canonical cone. The combined piezooptic coefficient for lead germanate crystals is determined experimentally. It is shown that, for all of the point symmetry groups of trigonal system, the torsion torque applied around the directions of optic axes would lead to appearance of a purely screw dislocation of the phase front of the outgoing wave, while the corresponding optical vortex would possess a unit topological charge. Source

Skab I.,Institute of Physical Optics | Vlokh R.,Institute of Physical Optics
Applied Optics | Year: 2012

Acousto-optic diffraction of light in optically active cubic crystals is analyzed from the viewpoint of conservation of optical angular momentum. It is shown that the availability of angular momentum in the diffracted optical beam can be necessarily inferred from the requirements of angular momentum conservation law. As follows from our analysis, a circularly polarized diffracted wave should bear an orbital angular momentum. The efficiency of the spin-to-orbit momentum conversion is governed by the efficiency of acousto-optic diffraction. Source

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