We generate higher-order azimuthally modulated Bessel optical lattices in photorefractive crystals by employing a phase-imprinting technique. We report on the experimental observation of self-trapping and nonlinear localization of light in such segmented lattices in the form of ring-shaped and single-site states. The experimental results agree well with numerical simulations accounting for an a...

We report on experimental and theoretical studies of a photorefractive ring resonator pumped by a 1.06 mm beam and injected with a weak, external, seeding beam. The competition between the two dominant gratings that form inside the photorefractive crystal leads to characteristic periodic oscillations in the intensity of the resonating beam, which originate from the frequency difference between ...

We demonstrate experimentally the formation and stable propagation of bound soliton pairs in a highly nonlinear photonic crystal fiber. The bound pairs occur at a particular power as the consequence of high-order soliton fission. They propagate over long distances with constant inter-soliton frequency and time separation. During propagation, the soliton self-frequency shift causes the central f...

This is a survey on Chaos in Partial Differential Equations. First we classify soliton equations into three categories: 1. (1+1)-dimensional soliton equations, 2. soliton lattices, 3. (1+n)-dimensional soliton equations (n ≥ 2). A systematic program has been established by the author and collaborators, for proving the existence of chaos in soliton equations under perturbations. For each categor...

We calculate the photorefractive grating amplitude in the presence of a high-frequency applied electric field in terms of the mean-square drift length of the charge carriers. We describe how a shallow-trap level and the related long effective deep-trap recombination time are detrimental to the enhancement produced by a squarewave field. We give expressions for the shallow-trap-induced reduction...

This paper reviews our recent work on the photorefractive effect of ferroelectric liquid crystals (FLCs). The photorefractive effect is defined as the optical modulation of the refractive index of a medium as a result of a variety of processes. The interference of two laser beams in a photorefractive material establishes a refractive index grating. This phenomenon enables the creation of differ...

PURPOSE To report the effect of wavefront-guided photorefractive keratectomy and corneal collagen cross-linking (CXL) on visual problems after Ferrara ring segment placement. MATERIALS AND METHODS A 32-year-old male patient was treated with a Ferrara ring segment for keratoconus. One year later, the ring was removed due to severe glare complaints. After 6 months, wavefront-guided photorefract...

We demonstrate a photorefractive incoherent-to-coherent optical converter driven by ultraviolet light that provides a 35-mus response time and an optical resolution of 124 line pairs/mm. The device, implemented in KNbO(3) , operates with a modulating intensity of 85 mW/cm(2) , which corresponds to an optical switching energy per bit of 0.5 pJ. A conversion rate of the order of 90 Gbits/(s cm(2)...

The regularities of energy transfer between two linearly polarized light waves as their contra-directional mixing on a volume reflection holographic grating formed in photorefractive Bi12GeO20 crystal the (001)-cut are analyzed. values thickness and azimuths linear polarization waves, at which amplification object wave is achieved, determined. change direction to opposite, depending crystal, ha...

PURPOSE To evaluate the efficacy of unilateral photorefractive keratectomy to correct anisometropia induced by retinal detachment surgery. METHODS Photorefractive keratectomy was performed in 10 eyes of 10 patients with anisometropia induced by previous retinal detachment surgery. The Aesculap Meditec MEL 60 excimer laser was used. RESULTS Preoperative mean spherical equivalent refraction w...