Experimental comparison of the output beam quality for the Nd：glass slab laser with VRM

By using different types of resonators with different VRMs for the Nd:glass slab laser,the experiments have been performed and the output beam quality has been compared.A comparison with plane concave resonator has been made too.The diagnostic system has been tested and verified,the measurement results are correct,the results obtained in this paper would be useful for the application of VRM to the slab laser.