表面张力是表征液体表面性质的物理量,其测量在医学、表面物理等领域中具有重要的研究意义.本文提出了利用数字全息的方法实现非接触、高精度液体表面张力的测量. 首先搭建了基于MachZehnder干涉光路的无透镜傅里叶变换数字全息装置，对CCD拍摄的全息图进行傅里叶逆变换,实现数值再现，再利用傅里叶变换的位相解包裹算法获得相位图，进而得到静态液滴的剖面轮廓. 将液滴剖面轮廓与杨-拉普拉斯显式精确解进行拟合得到液体的表面张力系数. 通过多次测量得到在温度20℃下水表面张力系数的相对误差为0.42%.

Surface tension is a physical quantity which characterizes the surface properties of liquid. Its measurement has important research significance in the fields of medicine, surface physics and so on. In this paper, a method of digital holography is proposed to realize the non-contact and high-precision measurement of liquid surface tension. Firstly, a lensless Fourier transform digital holographic device based on Mach Zehnder interference light path is built. The hologram taken by CCD is numerically reconstructed by inverse Fourier transform. The phase diagram is obtained by using the phase unwrapping algorithm of Fourier transform, and then the crosssectional profile of static droplets is obtained. The surface tension coefficient of liquid is obtained by fitting the droplet profile with the explicit and accurate solution of Yang-Laplace equation. The relative error of water surface tension coefficient at 20℃ is about 0.42%.