A diode-pumped discrete-element ring laser that can be end pumped simultaneously along two intersecting axes is described. The maximum power obtained was 493-mW single frequency at 1.06 µm. A demonstration of cw and Q-switched operations was performed for the fundamental and second harmonic, and a second-harmonic conversion efficiency of 43% was obtained. This ring laser is shown to incorporate significant advantages in terms of alignment and scalability.
Richard Scheps and Joseph F. Myers, "Scalable single-frequency diode-pumped ring laser," Appl. Opt. 31, 1221-1224 (1992)