We demonstrate, theoretically and experimentally, that dipole-mode vector solitons created in biased photorefractive media possess a number of anisotropy-driven properties, such as stability of a selected orientation, wobbling, and incomplete rotation, owing to the anisotropic nonlocal response of the photorefractive non-linearity. Such features are found for higher-order (multipole) vector sol...

We study experimentally self-trapping of optical beams in photorefractive media and show that the trapping is inherently asymmetric with respect to the two (transverse) trapping dimensions. We also present experimental results that show how the sizes of the resultant photorefractive spatial solitons are independent (within their range of existence) of the amplitude of the externally applied ele...

We report the fixing of a photorefractive grating in KTa(1-x)Nb(x)O(3). The procedure involves the writing of a photorefractive grating in the cubic phase and the cooling of the sample under an applied field into the rhombohedral phase. We discuss possible mechanisms responsible for the effect.

We study theoretically and experimentally the modulational instability of broad optical beams in photorefractive nonlinear media. The angular dependence of the growth rate of periodic perturbations is calculated. Our findings are confirmed by experimental measurements on a strontium barium niobate photorefractive crystal.

We report the experimental demonstration of a photorefractive dynamic holographic memory that has a simple feedback architecture stabilized through a novel spatial sampling technique. By using dynamic copying to compensate for photorefractive decay, this memory provides nondestructive readout, selective erasure and rewriting, and real-time adaptation of holograms through an arbitrarily large nu...

Double gratings form in anisotropic photorefractive crystals when two plane waves intersecting inside the crystal have both extraordinary and ordinary wave components. The effect can be observed by reading out the two gratings with extraordinary or ordinary light. Experiments confirm the theoretical predictions. The relevance of these results in using photorefractive crystals for holographic st...

We predict the formation of optical spatial solitons in photorefractive polymers. The orientational enhancement from the doped chromophores and the dependency of the quantum efficiency of generating mobile holes on the electric field make the polymeric solitons behave differently from other photorefractive solitons.

We demonstrate optical waveguiding of a probe beam at 980 nm by a soliton beam at 780 nm in an organic photorefractive monolithic glass. Both planar and circular waveguides induced by one- and two-dimensional spatial solitons formed as a result of orientationally enhanced photorefractive nonlinearity are produced in the organic glass. Possibilities for increasing the speed of waveguide formatio...

A 39-year-old woman presented to our hospital with a history of photorefractive keratectomy (PRK), performed two weeks prior; slit-lamp examination revealed diffuse conjunctival congestion, corneal ulcer and stromal infiltration. After 5 days of antifungal and antibacteric treatment, the infiltrate progressively increased so that a therapeutic penetrating keratoplasty was necessary. The microbi...

Two cases of necrotizing keratitis following laser refractive corneal surgery, with stable and controlled Crohn's disease are described. A 40-year-old woman developed bilateral stromal inflammation and inferior thinning in the right eye along the flap edge within 1 day of uneventful bilateral IntraLase laser-assisted in situ keratomileusis. The other case is a 30-year-old man who also developed...