Electrically variable liquid crystal lens based on the dielectric dividing principle.

Theoretical modeling is performed for a liquid crystal (LC) lens that uses a combination of two dielectric lenses and voltage dividing principle to shape the electric field in space. Electric field, LC reorientation, and optical phase retardation profiles are obtained by numerical simulations. The obtained results are compared with experimental ones, and good agreement is obtained validating the proposed two-dimensional model that uses a limited number of dielectric and geometrical control parameters for this type of lens.

Optical lens with electrically variable focus using an optically hidden dielectric structure.

Electrically variable gradient index liquid crystal lens is developed that uses flat uniform liquid crystal layer and electrodes. The spatial modulation of the electric field across the lens aperture is obtained by the modulation of the effective dielectric constant of an integrated doublet lens structure. The dielectric constants of two materials, composing the doublet, are chosen to be different at electrical driving frequencies, while their optical refractive indexes are the same, hiding thus the structure from the optical point of view. This "hidden layer" approach decouples the electrical and optical functions of that structure, increases significantly the performance of the lens and enables new functionalities. The technical performance and various driving schemes of the obtained lens are presented and analyzed.

Optical polarization grating induced liquid crystal micro-structure using azo-dye command layer.

We create planar-periodic alignment in nematic liquid crystal (LC) cell by using a command layer of azo-dye molecules directly deposited on the cell substrates and exposed with two interfering laser beams of opposite circular polarizations. Permanent high efficiency polarization gratings are thus created. The diffraction efficiency of those gratings is controlled by a uniform electric field applied across the cell. The electro-optical properties of such polarization gratings are studied. Obtained gratings can be used for electrically controlled discrimination and detection of polarized components of light.

Polymer-stabilized liquid crystal for tunable microlens applications.

We investigate the electro-optical properties of polymer stabilized nematic liquid crystals produced by in situ photopolymerization technique using Gaussian laser beam. The distribution of refractive index in such structure under the action of a homogeneous electric field reveals a non-homogeneous lens-like character, approximately reproducing the intensity transverse distribution in the photopolymerizing beam.