… gratings in photorefractive crystals, based on the assumption of two types of active centers
being … It is demonstrated that a photorefractive grating can change its phase by 1800 during …

… the capabilities of photorefractive crystals [21–28]. The photorefractive effect consists of …
Typical doping levels of photorefractive centers are in the range 50–1000 mol ppm and also …

… reduction of the crystal, which may be advantageous for photorefractive applications. However,
the … -related EL2 center is thought to be responsible for the photorefractive effect (81). The …

… Here we mean the crystals that lack a center of inversion where the linear and circular
photovoltaic effects are observed [1.17]. The preferred direction in space is then governed by the …

… crystals, newer photorefractive materials. Special emphasis is given to the ap plication of
photorefractive … impurity centers, therefore the char acterization of the photorefractive material is …

… photorefractive materials containing multiple active centers. … of charge among the various
centers and the holographic … two active centers, an optical donor and a thermally active trap. …

… photoactive center levels in undoped photorefractive Bi 12 Ti O 20 (BTO) crystals grown in
Brazil. Comparative results for Pb-doped BTO and Bi 12 Ga O 20 are also reported. A center …

… act as photorefractive trapping centers can be obtained from … who grow and use photorefractive
crystals is the accurate … and defects between which photorefractive charges migrate. …

… a single impurity center. Let N be the concentration of those active centers presenting two …
These effects have been observed in several crystals such as Bi12SiO20 [62], KNbO3 [63,64…

… in photorefractive materials with strong optical activity and absorption. These solutions
show the occurrence of breathing solitons in sillenite crystals with strong optical activity and …