提出了一种基于数字全息显微技术（digital holographic microscopy，DHM）的光聚合物折射率测量方法。采用马赫-曾德尔离轴干涉系统记录光聚合物的数字全息图，用混合重建算法提取高精度的相位分布。结合光学轮廓仪测量的光聚合物的形貌分布，通过图像配准得到光聚合物的折射率分布。定量分析了光聚合物在紫外固化过程中的折射率变化，利用DHM获取光聚合物的动态相位分布，进而得到光聚合物的动态折射率分布，绘制了平均折射率随曝光时间的变化曲线。该方法可用于揭示微光学元件的光学性能，以设计高质量微光学系统。
A method based on the digital holographic microscopy (DHM) for measuring the refractive index of photopolymer is proposed. The digital hologram is recorded by the Mach-Zehnder off-axis interference system. The high-precision phase distribution is extracted by the hybrid reconstruction algorithm. Combining the profile distribution measured by optical profilometer, the refractive index of photopolymer is obtained by image registration. The evolution of refractive index of photopolymer during the UV curing process is quantitatively analyzed. The dynamic phase distribution of photopolymer is measured by DHM, and then the dynamic refractive index distribution is obtained. The relationship between the average refractive index and exposure time is plotted. The proposed method can be used to reveal the optical performance of microscopic optical devices and design high-quality optical systems.
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