提出了一种可广泛适用于截断光束和非截断光束的广义M2因子测量的实验方法和相应的数据处理方法。在利用广义强度二阶矩计算光束束宽时,以积分角谱范围能够包含光束总能量的75%以上作为积分范围的选取标准,并遵循现有的国际标准化组织(ISO)规定的测量步骤和方法对截断高斯光束的广义M2因子进行了测量,并将不同截断参量时的实验结果与理论计算结果进行了比较,证明了该方法的正确性。研究结果表明,根据该方法测量截断光束M2因子时,只须将非截断光束M2因子测量的数据处理部分进行适当修正,而无需增加其他硬件开销,该方法简便易行且测量步骤仍可遵循国际标准化组织规定。

A method for the generalized M2 factor measurement and the corresponding data processing have been proposed, which can be widely applied to the truncated and non-truncated laser beams. The integral area for calculating the beam width by using the definition of generalized second-order moments is selected to ensure the energy in the angular domain more than 75% of the total beam energy and the measurement method and steps still follow the relevant ISO standards. The generalized M2 factor of truncated Gaussian beam has been measured. The experimental results for different truncated parameters have been compared with the theoretical results, showing the validness of the method proposed. The results indicate that the generalized M2 factor of truncated laser beam can be measured only by properly modifying the data processing method for the measurement of M2 factor of non-truncated laser beam without additional hardware spending. The method is simple and convenient and its measuring steps also follow the ISO standards.