A photorefractive organically modified silica glass with high optical gain
A photorefractive organically modified silica glass with high optical gain
复制标题
DOI：
10.1038/35040513
复制
发表时间：
2000-11
期刊：
影响因子：
64.8
通讯作者：
P. Cheben;F. Monte;D. Worsfold;D. Carlsson;C. Grover;J. Mackenzie
中科院分区：
文献类型：
--
作者：
P. Cheben;F. Monte;D. Worsfold;D. Carlsson;C. Grover;J. Mackenzie
由于光生电荷在光学非线性介质中的重新分布，光折变材料表现出折射率的空间调制。因此，它们具有操纵光的能力，并且对于包括图像处理、光学存储、可编程光学互连和神经网络模拟在内的光学应用具有潜在的重要性。光折变材料通常是具有电光或双折射特性的晶体、聚合物和玻璃等非中心对称结构。在这里，我们报告的光折变效应，在非中心对称和中心对称的偶氮染料掺杂的石英玻璃，其中观察到的折射率光栅的空间相移相对于入射光强度图案。这种效应是由于材料对光学照明的非局部响应造成的，并且能够在两个干涉光束之间传递能量（不对称双光束耦合）。虽然本光栅的写入时间相对较慢，但在中心对称玻璃中获得了188 cm-1的双光束耦合光学增益，在非中心对称结构中获得了444 cm-1的增益。后者是使用电晕放电过程来诱导偶氮染料发色团的永久排列而制造的。
Photorefractive materials exhibit a spatial modulation of the refractive index due to redistribution of photogenerated charges in an optically nonlinear medium. As such, they have the ability to manipulate light and are potentially important for optical applications including image processing, optical storage, programmable optical interconnects and simulation of neural networks. Photorefractive materials are generally crystals, polymers and glasses with electro-optic or birefringent properties and non-centrosymmetric structure. Here we report the photorefractive effect in both non-centrosymmetric and centrosymmetric azo-dye-doped silica glasses, in which refractive index gratings that are spatially phase-shifted with respect to the incident light intensity pattern are observed. The effect results from a non-local response of the material to optical illumination, and enables the transfer of energy between two interfering light beams (asymmetric two-beam coupling). Although the writing time for the present grating is relatively slow, we have achieved a two-beam coupling optical gain of 188 cm-1in the centrosymmetric glasses, and a gain of 444 cm-1in the non-centrosymmetric structures. The latter are fabricated using a corona discharge process to induce a permanent arrangement of azo-dye chromophores.