激光光束质量的管理在高功率激光放大系统中是一项非常重要的研究课题。项目利用放大器中增益介质热效应对光束波前的调制，通过空间传播在焦点后获得与初始像差反号的波前畸变，再利用下一级放大器中增益介质自身的热效应对光束的波前进行补偿，从而在多级激光放大器中实现M2因子恶化--改善--再恶化--再改善的周期性变化，通过这一方式达到对激光光束质量主动管理的目的。.重点研究波前具有像差的光束在空间传播的一般规律，搭建不同类型、不同参数的多级激光放大系统进行实验验证，实现这一方法在固体棒状介质、板条状介质以及光纤和固体混合结构等不同类型的放大系统中进行光束质量有效管理的目标。.这一研究对于激光光场的传播与控制具有重要的科学意义，同时在高功率固体激光放大系统中具有重要的应用价值。

Beam quality management is an important research topic in high power laser amplifiers. In this project, a method is presented for active beam quality management by periodically changing the M2 factor in multi-stage laser amplifiers. The wavefront of the input beam is modulated by the thermally induced aberrations in the gain medium of the amplifier. The wavefront aberration of the beam changes its sign when it propagates after the focus. Another amplifier is properly positioned to compensate the beam wavefront and finally to improve the beam quality. This process is periodically performed in multi-stage laser amplifiers to realize the active beam quality management..The emphasis is on the propagating rules when an aberrated laser beam propagates in a free space. Experimental studies will be carried out for various laser amplification systems with different parameters, especially for amplifiers with rod or slab gain mediums, or fiber-solid hybrid amplification systems..This research has great significance in the field of laser beam propagating and beam controlling. It is also significant to the practical applications of high power laser amplification systems.