中文摘要：

提出了一种简便和精确地计算毛细管管壁折射率的方法，该计算方法可在实际非近轴情况下减小图像球差和景深对测量结果的影响。用两种已知折射率的标准液体分别注入待测毛细管内，测量出平行光经其会聚后的焦距差；结合毛细管管壁折射率与焦距的理论公式，计算出毛细管的管壁折射率。结果表明：在合适的毛细管内外径范围内，可以保证管壁折射率在1．51以下时测量准确度优于0．003。对计算方法的分析表明，选取两种低折射率或高折射率液体作为标准液体进行计算可以提高测量准确度。该方法计算过程简单，对毛细管管壁折射率的测量精度满足一般科研实验对毛细管管壁折射率的要求。

英文摘要：

A new method to calculate the refractive index of a capillary wall simply and accurately was proposed to reduce the effects of the spherical aberration and the depth of field on measurement re- sults under a non-paraxial condition. Firstly, two kinds of standard liquids with known refractive indexes were filled into a capillary, respectively, and the distance between two focal positions were measured when the collimated light passed through the capillary. Then, by using the formula of the refractive index of capillary wall and the focal length, the refractive index of the wall-material could be obtained. The experimental results indicate that the measurement accuracy of refractive index is better than 0. 003 when the refractive index of wall-material is less than 1. 51 in the proper inner and outer diameters of a capillary. It is demonstrated when two kinds of low （high） refractive index liquids are chosen as standard liquids, the measurement accuracy can be improved. The introduced method has a simpler calculation process and its measurement precision of refractive index meets the requirements of general scientific research.