本文提出了一种基于消球差复合液芯柱透镜快速、准确测量液体折射率的新方法——液芯柱透镜散焦宽度法．该方法利用消球差复合液芯柱透镜在较宽折射率范围内系统球差小、成像准确的特点，基于不同折射率在成像系统上呈现一一对应的散焦图像，仅需采集一幅散焦图像即可得到待测液体的折射率．用该方法测量了室温( 20 ℃)下21组不同液体的折射率，测量结果与用阿贝折射仪测量结果一致，用ZEMAX和光线追迹逐面成像法仿真的散焦宽度图像与实验图像一致．用该方法测量液体折射率具有系统简单、稳定性好、操作简便、测量速度快等特点．

In this paper, a new method for measuring liquid refractive index based on a spherical aberration-free liquid-core cylindrical lens is presented by analyzing an experimental defocused image on the focal plane. A spherical aberration-free liquid-core cylindrical lens is designed and fabricated which has small spherical aberration and accurate imaging in a wide range of refractive index. Using the designed lens, according to the relationship between the experimental image and the liquid refractive index, only one defocused image is needed to measure the liquid refractive index. The method is used to measure the refractive indexes of 21 groups mixed solution at room temperature (20℃). The measured results are in well agreement with those using Abbe refractometer. The defocused images simulated by ZEMAX and ray tracing method are consistent with the experimental results. The experimental and simulation results show that the method has the characteristics of simple system, good stability, simple operation and fast measurement speed.