Photorefractive Effects

Alexander M. Glass

Yu. V. Vladimirtsev, N. N. Kurkin, Yu. E. Nesmelov +1 more

Philippe Delaye, P. U. Halter, Gérald Roosen

Although the excited state of Fe2+ is well known in InP:Fe (figure 1), its influence on photorefractive effect has never been taken into account. We report here a study of this influence and show that the presence of this state induces in the photorefractive effect a new hole-electron competition. This theory well explains the photorefractive coupling gain results obtained on a crystal without any classical hole-electron competition(αn«αp).

Wies aw Kr�likowski

Russell M. Kurtz, Weixing Lu, Judy Piranian +1 more

Photorefractive optical amplification, while useful, is a slow process. Under some circumstances, however, it amplifies optical signals effectively even when one is modulated at a relatively high frequency. We determine the reasons for this capability (what we have called the "Fast Photorefractive Effect") and analyze its enhanced bandwidth, improvements over standard photorefractivity, and limitations.

Zheng Guang-zhao

It is reported to test the additional phase difference of two beams along two opposite directions in the photorefractive crystal using Sagnac interferometer. The additional phase difference is demonstrated by experiments when two beams of laser transit along two opposite directions in the photorefractive crystal. The experimental results show that the additional phase difference is dependent on the direction of optical axis of the photorefractive crystal. They mean the existence of the additional optical path difference when two beams of laser transit along two opposite directions in the photorefractive crystal. The effect may be named the effect of bilateral phase in the photorefractive crystal. Its cause may be the same as the fanning effect.