title: Method to improve beam quality by compensating spherical aberrations in master oscillator power amplifier laser systems.
abstract: A method is presented for beam quality improvement, in master oscillator power amplifier laser systems. Intensive study was first carried out with the beam wavefront evolution in a laser resonator. When the laser beam propagates inside the resonator, the spherical aberration coefficient of the beam wavefront can change sign, i.e., the negative spherical aberration coefficient can turn to positive, and vice versa. This process also occurs when the beam propagates outside the resonator in a free space. The laser beam, from an oscillator with negative spherical aberration, was found to be well-compensated by the positive spherical aberration of a strongly pumped laser rod in a laser amplifier. The laser beam quality M2factor has been significantly improved, from 2.2 to 1.4, while the output power has been scaled from 31 W up to 60 W.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Ye
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhao
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xiang