论文部分内容阅读
在光折变过程中,光波对掺杂中心的激发系数S是一个重要的物理量。为了求出光激发系数S对波长λ的依赖,研究了在不同的擦除波长条件下,记录在光折变晶体LiNbO3∶Fe中的光栅衰减特性。实验结果表明lnP(P为光擦除灵敏度)与擦除波长λ呈线性关系,即波长越短,光栅擦除越快,光擦除灵敏度越高。在单中心电子带传输模型的基础上,理论计算也证实了实验结果。利用带传输模型,给出了理论上光激发系数S对波长的指数依赖关系。同时微观量μτ(为量子效率)也可由光栅擦除实验求出。
During the photorefractive process, the excitation coefficient S of the light wave to the doping center is an important physical quantity. In order to obtain the dependence of the photoexcitation coefficient S on the wavelength λ, the grating attenuation properties recorded in the photorefractive crystal LiNbO3: Fe at different erasing wavelengths were studied. The experimental results show that lnP (P is the optical erasing sensitivity) is linear with the erasing wavelength λ. That is, the shorter the wavelength, the faster the raster erasing and the higher the optical erasing sensitivity. On the basis of single-center electronic belt transmission model, the theoretical calculation also confirmed the experimental results. Using the band transfer model, the theoretically exponential dependence of the optical excitation coefficient S on the wavelength is given. At the same time the amount of microscopic μτ ( for the quantum efficiency) can also be obtained by the grating erase experiment.