利用全息法在偶氮聚合物薄膜中记录涡旋光场

利用全息技术在偶氮聚合物薄膜中记录了拓扑荷数q=–1,1,2,4的涡旋光场,并将记录的原始叉形光栅与计算全息光栅进行对比,对不同拓扑荷数涡旋光的记录速率和偶氮材料的可重复擦写性能进行了测试;记录完成后,将复现涡旋光与高斯光束干涉,并与原始涡旋光和原始叉形光栅对比,分析了记录质量.实验结果表明:高阶涡旋光场的全息叉形光栅会在记录过程中发生劈裂,轻微劈裂的涡旋光束仍维持一个稳定的环状结构;全息记录过程中不同拓扑荷数的涡旋光束记录速率较为统一,偶氮材料可经过上百次的擦写而不出现疲劳;再现涡旋光与原始涡旋光在光强分布结构上保持高度一致,再现涡旋光的干涉条纹与原始涡旋全息光栅保持高度一致,涡旋光及其携带的拓扑荷信息可被有效记录和读取.

Recording optical vortices in azo polymer films by applying holographic method

In this paper the optical vortices with topological charge q=-1,1,2,4 are recorded in azo polymer films by using holographic technology.The forked holographic gratings formed by the Gaussian beam and optical vortex beam are recorded in the sample films,the original forked holographic grating and the recording rate are analyzed.The vortex beam is reconstructed by illuminating the sample film with a reference beam,and the recording quality is analyzed.Also the erasability and durability of the sample are tested.The experimental results show that the recording rates of vortex beams with different topological charges are relatively uniform,which means that the optical vortices with different topological charges can be recorded at the same speed.The forked holographic grating of the high-order optical vortex splits in the recording process due to the disturbances,such as anisotropic nonlinear light,atmospheric turbulence,and background light field.However,the split vortex beam still maintains a stable ring structure.The reconstructed optical vortex and the original optical vortex are highly consistent in morphology,and the interference fringes of the reconstructed optical vortices are highly consistent with the original vortex holographic gratings,indicating that the topological charge information in the optical vortices can be effectively recorded and read out.The recorded information can be erased by heating the sample to about 97℃,and new information can be re-recorded after cooling.There appears no fatigue in the sample after the information has been erased 100 times and good durability is still retained.Optical vortices theoretically have infinite states of topological charges,based on which great success is achieved in optical communication and information encoding.Therefore,storing and reading information of topological charges in optical vortices may have potential applications in optical information storage.