Improvement of Index Distributions for GRIN Lens by Two-step Ion-exchanging Method
二次离子交换法改进自聚焦透镜折射率分布

The two-step ion-exchanging method for fabrication of GRIN lens is proposed. The mixed salts of KNO3 and NaNO3 are used in the process of two-step ion-exchanging, and the result is satisfactory. The index distributions and aberrations are also measured. As a result, the index distributions are amended greatly and they are much more close to the ideal index distributions and the aberrations are decreased from 13.1% to 7.7%.