为了精确测量零阶贝塞耳光束的中心亮斑半径，采用彩色反转胶片作为记录媒质，通过滚筒扫描的方法将底片上的图像转为数字图像，在对数字图像做必要的处理后，测量出氦氖激光的零阶贝塞耳光束的中心光斑半径为16．77μm±0．01μm，与理论计算值15．16μm吻合良好。实验结果表明，采用胶片测量微米量级的光斑具有高精度、低成本，可测截面面积大的优点，在1Hz超短脉冲实验中，可以替代甚至超越了常规的激光光束分析仪。

Using color reversal film as record medium,the radius of the Bessel beam central spot is measured through the analysis of the digital image by film-scanning. The experimental result 16.77μm±0.01μm is consisted well with the theory result 15.16μm. The result also indicates that the film-scanning method shows some advantages in lower cost,higher accuracy and larger measurable scale. Furthermore,this measurement is superior to the expensive laser beam parameter analyzer in measuring the beam size on micrometer magnitude of 1 Hz ultrashort pulse.