激光的参数描述和光束质量

激光光束质量是一个很有现实意义的论题。对实际激光，一方面或多或少存在硬边光阑光学元件影响。另一方面，人们常对远场激光束的可聚焦能力感兴趣。对有光阑情况时光束传输因子(M^2因子)的推广作了讨论。对有代表性的3种方法，即广义截断二阶矩法、渐近分析法和自收敛束宽法及其应用作了分析。引入了桶中功率(PIB)和β参数用以描述远场光束质量。然后，研究了实际应用对激光光束质量的一些要求和相关的评价参数。最后，讨论了复杂的高功率激光系统的全程光束质量控制问题。

Parametric characterization of laser beams and beam quality

The laser beam quality is a topic of current interest. For a real laser, there exists hard-aperture optics more or less. On the other hand, the people are often concerned about the focusability of laser beams in the far field. The extension of the beam propagation factor (M~2 factor) to the apertured case is discussed. Three typical approaches to truncated beams, i.e. the generalized truncated second-moments method, asymptotic analysis and self-convergent-beam-width method, as well as their applications are analyzed. The power in the bucket (PIB) and β-parameter are used to characterize the beam quality in the far field. Then, some practical requirements for the laser beam quality and related characteristic parameters are studied. Finally, a brief discussion about the beam quality control of a complicated high-power laser system as a whole is made in this paper.