Abstract:In order to solve the difficulty of high precision measurement and evaluation of the surface morphology of laser fusion target, a laser differential confocal sphericity measurement and evaluation method for the laser fusion target is proposed. This method uses the property that the zerocrossing point of the axial response curve of the laser differential confocal measurement system corresponds to the focus point position of the objective lens to realize the target surface focusing. Through rotating the target in two orthogonal directions respectively, a number of crosssections of the target surface are measured and acquired; and the whole morphological structure measurement for the target is achieved. The minimum zone sphericity evaluation algorithm is used to establish the threedimensional model for the target sphericity evaluation, the quantitative evaluation of the target morphological structure is conducted. Based on the method, an experiment system was built to perform the morphological structure measurement of the target surface. The evaluation results show that with the proposed method the measurement repeatability reaches 0.15 μm, which provides a feasible scheme for the morphological structure measurement of fusion target.