Laser amplifier and method for improving light beam quality

The invention discloses a laser amplifier for improving light beam quality, and so that the light beam quality of the laser amplifier can be improved obviously. The invention further discloses a method for improving the light beam quality based on the laser amplifier. The adjustment of the position of an amplifier stage can effectively control the light beam quality of amplifier stage output. Not only can experimental apparatus be simplified, light path length is greatly shortened, laser power is guaranteed to be amplified, and meanwhile, the improvement of the light beam quality can be achieved. Namely, light beam quality which is output from an oscillator stage is poor, the light beam quality after the amplifier stage is improved, and therefore the whole device can obtain high power laser output with good performance.