基于自参考干涉的光束质量M2因子测量方法及关键技术研究

M2因子是衡量激光光束优劣的重要指标，它的评估与测量在应用激光领域具有重要意义。然而传统M2因子需要多次测量方可获得，不仅操作繁杂、耗时长，且无法用于瞬态激光光束质量的评价与测量。本项目拟发展一种基于自参考干涉(SRI)的M2因子实时测量方法，并对其关键技术作系统的理论与实验研究，主要内容如下：首先根据国际标准ISO11146规定的M2因子测量方法，建立以激光复振幅信息为基础的M2因子测量方法理论模型；其次搭建基于SRI的M2因子测量系统，利用理论分析、数值仿真与实验研究等手段揭示针孔直径、放大倍数S、去载频误差等关键因素对激光复振幅重建和M2因子测量精度的影响规律，实现对M2因子测量系统的完善与优化；最后实验研究M2因子测量方法与系统的可行性，实现对瞬态激光M2因子的实时测量。本项目的研究可望为脉冲激光或瞬态激光的光束质量评价与测量等研究领域提供相关理论基础与技术支持。

Beam quality factor M2 is an important indicator to measure the performance of a laser beam, it’s also one of the most commonly and widely accepted parameters for beam quality evaluation and characterization method, and it’s has great significance in the fields of the laser’s theoretical analysis, design, manufacture and various applications. However, the traditional M2 factor is the result of the multiple moving measurements, which results in complex operations, time-consuming, and unable to realize the measurement for beam quality M2 factor of the transient laser system in real-time. Here, a novel real-time measurement of beam quality M2 factor based on self-referencing interferometer (SRI) is proposed, and the main contents are as follows: Firstly, according to the international standard, ISO11146, of the M2 factor measurement method, the theory model of measurement method for M2 factor, which with the basis of complex amplitude information of the measured laser beam, is established. Secondly, the real-time measurement experimental system for M2 factor based on SRI is built, the influence laws of pinhole diameter, magnification of the SRI, and the carrier frequency error on the measuring precision of the reconstruction complex amplitude and the M2 factor of laser beam, respectively, are revealed by using of the related theory analysis, numerical stimulations, and experimental studies with the SRI experimental system. Moreover, according to the correction results, the experimental measurement system for M2 factor are optimized and perfected. Finally, the feasibility of the M2 factor measurement method and the experimental system based on SRI are performed with experimental studies, in order to realize the transient laser beam quality factor M2 measurement in real-time. The objective of the study’s results is expected to provide theoretical foundations and technical supports for research fields in pulse laser or transient laser beam quality evaluation and application.