We report the growth and characterization of a new photorefractive material, potassium lithium tantalate niobate (KLTN). A KLTN crystal doped with copper is demonstrated to yield high diffraction efficiency of photorefractive gratings in the paraelectric phase. Voltage-controllable index gratings with n(1) = 8.5 x 10(-5) were achieved, which yielded diffraction efficiencies of 75% in a 2.9-mm-t...

A quantitative analysis of the steady-state photorefractive index perturbations caused by a given optical irradiance distribution in a periodically poled ferroelectric is presented. Axially invariant index perturbations that are due to the photogalvanic effect are reduced compared with those in a homogeneously poled crystal by approximately the square of the product of the poling-grating wave v...

Oscillatory mode coupling between two coherent laser beams is produced when an interference pattern moves against a quasi-static electrically strobed grating in a photorefractive AlGaAs/GaAs multiple-quantum-well diode operated in the quantum-confined Stark geometry. The oscillation frequency is equal to the frequency difference between the two laser beams and provides a method to measure high-...

We report the fixing of photorefractive holographic gratings with high efficiency in a sample of K(1-y)Li(y)Ta(1-x)Nb(x)O(3) doped with Cu, V, and Ti. Holograms are thermally fixed through the screening of a photorefractive space-charge f ield by a nonphotoactive species at elevated temperatures. Fixed holograms are revealed by illumination at lower temperatures. Diffraction efficiencies of 25%...

Time-reversed ultrasonically encoded (TRUE) optical focusing achieves light focusing into scattering media beyond one transport mean free path, which is desirable in biomedical optics. However, the focused optical energy needs to be increased for broad applications. Here, we report the use of a photorefractive polymer (PRP) as the phase conjugate mirror in TRUE optical focusing. The PRP boosted...

The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mism...

We demonstrate that the spatially modulated electric field that is associated with a photorefractive grating generates stress and strain components with symmetries that are different from those induced by a uniform electric field. Therefore, because of piezoelectricity and the elasto-optic effect, the symmetries of the effective dielectric and electro-optic constants to be used to describe the ...

PurposeTo review the literature to evaluate outcomes of intraocular lens (IOL) power calculation in eyes with a history myopic LASIK or photorefractive keratectomy (PRK).MethodsLiterature searches were conducted PubMed database January 2020. Separate relevant cataract surgery and corneal refractive returned 1169 162 citations, respectively, full text 24 was reviewed. Eleven studies met inclusio...

We screened 46 ophthalmology journals to identify the most frequently cited articles using the Science Citation Index Expanded (1975 to 2006). The 100 most-cited articles were published in 13 journals, most in the Archives of Ophthalmology (n = 30), followed by Ophthalmology (n = 27) and the American Journal of Ophthalmology (n = 11), and originated from 10 countries, led by the United States (...

We provide a correction factor to be added in ablation algorithms when a Gaussian beam is used in photorefractive laser surgery. This factor, which quantifies the effect of pulse overlapping, depends on beam radius and spot size. We also deduce the expected post-surgical corneal radius and asphericity when considering this factor. Data on 141 eyes operated on LASIK (laser in situ keratomileusis...