In this paper, a model of two-wave mixing in the photorefractive crystal, which takes account of the difference in spatial frequency in a beam, has been built to study the image enhancement effect in coherent optical amplification. Based on the theoretical analysis of the model, the gain distribution for each pixel in the signal beam has been obtained. It shows that the unevenness of the gain i...

The parallel pixel acquisition inherent in wide-field coherence-gated imaging techniques offers the possibility of high-frame-rate imaging and volumetric imaging, including through scattering media. We discuss photorefractive holography using sensitive, dynamic photorefractive multiple quantum well (PRQW) films as a promising approach and, after reviewing the factors that determine the sensitiv...

Modulational instability in a photorefractive medium is studied in the presence of two wave mixing. We then propose and derive a model for forward four wave mixing in the photorefractive medium and investigate the modulational instability induced by four wave mixing effects. By using the standard linear stability analysis the instability gain is obtained. In both the cases, the geometry is such...

Abstract Background The refractive surgeries induce corneal higher order aberrations (C-HOAs). In this study, change of C-HOAs after small-incision lenticule extraction (SMILE) compared to femtosecond assisted laser in situ keratomileusis (femto-LASIK), and photorefractive keratectomy with mitomycin-C (PRK) under photopic mesopic conditions. Methods prospective age, gender, apical thickness (AC...

We discuss the influence of the limited available number of photorefractive centers on

We predict spatial solitons in photorefractive centrosymmetric media driven by the dc Kerr effect.

BACKGROUND Tetracaine and proparacaine are two of the most commonly used medications for providing topical anesthesia in laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). These agents have not been previously compared in a prospective manner to determine their efficacy in these settings. METHODS This prospective, single-masked, randomized study comprised 256 eyes fro...

OBJECTIVES To describe the refractive results of cataract surgery after photorefractive keratectomy (PRK) for patients with myopia, and to find a more accurate method to predict intraocular lens (IOL) power in these cases. DESIGN Nonrandomized, retrospective clinical study. PATIENTS AND METHODS Nine patients (15 eyes) who underwent cataract surgery after prior PRK to correct myopia were ide...