In the present paper, photoconductive and dielectric dependence oscillation characteristics of a single photorefractive ring resonator have been studied for the case of non-degenerate two-wave mixing in photorefractive materials by employing the plane-wave approximation method. The influence of photoconductivity and dielectric constant of photorefractive materials on frequency of oscillation an...

The photorefractive response to an applied electric field is measured in a photorefractive quantum well, providing evidence in favor of the nonlinear transport in the device due to the hot electrons. The reduced mobility of the hot electrons limits the drift length, and thereby limits fringe overshoot. Thus the nonlinear transport prevents the slowing down of the grating writing rate for increa...

OBJECTIVE Revision of methods for estimating corneal power (Kpost) and effective lens position (ELP) for cataract surgery after corneal refractive surgery. METHODS Review of medical literature. RESULTS To calculate the intraocular lens that achieves emetropia after corneal refractive surgery it is necessary to correct the Kpost and to estimate the effective lens position again correcting it...

Steep central island (SCI) formation after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) represents a major drawback in the visual rehabilitation of patients after refractive laser surgery. Because of the small size of SCIs, current ablation algorithms are unable to properly calculate an ablation pattern for customized retreatment. We present the use of a new ablati...

The photorefractivity of a photorefractive composite consisting of poly(N-vinylcarbazole) (PVK) doped with a non-room-temperature liquid crystal, 4-butyloxy4’-cyanobiphenyl (4OCB), and C60 was studied by means of measuring the two-beam coupling coefficients. The results show that the photorefractivity is enhanced by phase separation. PACS: 42.65; 61.30; 61.40 Interest in materials that exhibit ...

We present a review of keratorefractive and intraocular approaches to managing residual astigmatic and spherical refractive error after cataract surgery, including laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), arcuate keratotomy, intraocular lens (IOL) exchange, piggyback IOLs, and light-adjustable IOLs. Currently available literature suggests that laser vision correc...

Optical aberrations lead to defects in image-forming, the image obtained being imperfect and thereby decreasing the quality of vision. When an optic system is not perfect, as happens with the eye, the rays of light that pass through the system produce optical aberrations. The purpose of this review is to describe optical aberrations and their impact on vision and how refractive surgery outcomes...

We report the first observation, to our knowledge, of self-trapping of light as well as optically induced focusing-to-defocusing switching in an organic photorefractive glass, owing to the orientationally enhanced photorefractive nonlinearity of the material.

OBJECTIVE To assess intraocular lens (IOL) power calculations in patients undergoing cataract surgery after excimer laser photorefractive keratectomy (PRK) for myopia. METHODS Four eyes of two patients underwent phacoemulsification with IOL implantation after PRK for myopia. The estimated refractive error that would have been induced had the IOL predicted for emmetropia been implanted was cal...