LAUSR

Abstract The unstable ring resonator is a promising architecture for high power solid-state oscillators with intra-cavity adaptive optics. In this paper, we present adaptive compensation of intra-cavity tilt in an Nd: YAG unstable ring laser using a probe beam and a far-field camera to detect the tilt. A numerical model of the ring resonator is established based on the Fox–Li method, through which the influence of intra-cavity tilt is studied, and the optimal strategy of tilt correction is proposed and evaluated. An experiment with an unstable Nd: YAG slab ring laser is developed. With 40 μ rad tilt on the zigzag direction and 130 μ rad tilt on the non-zigzag direction compensated during lasing, the output power increased from 77.2W to 87.0W. The above results lay the foundation for adaptive optics techniques to compensate for the intra-cavity aberrations in high power solid-state unstable ring lasers.