作为柱腔填充材料，泡沫材料在装配后的形变特征是重要参数，需要精确表征。光学干涉技术可以获得样品表面以下1~2 mm深度内的层析结构图像，进而获得相关形变特征信息。利用光学干涉技术开展了对柱腔内泡沫质量的表征研究。搭建了一套基于低相干光源的光纤干涉系统，得到了装配后泡沫的二维和三维内部结构图像，空间测量分辨率好于10 μm。通过泡沫图像检测出萃取后存在表面或内部形变的泡沫样品，为装配后泡沫质量的表征提供了依据。

Precise measurement of foam shape after assembling is necessary. Optical interferometry can obtain cross-sectional structure images of sample with 1-2 mm depth below surface, therefore the shape change is observed. In this paper, optical interferometry is applied to quality demonstration of foam in hohlraum. An optical interferometer based on low coherent light source is established and inner structure images of assembled foam are obtained with a spatial resolution better than 10 μm. Superficial and inner structure changes of the foam after extraction are detected, which helps to demonstrate the quality of the assembled foam.