Mirror problems of a cw argon-ion laser at high output power

We report upon some experiments done on a continuous-wave argon-ion laser which offers 300 W output power in the visible and 34 W in the ultraviolet region of the spectrum, limited by the degradation of the resonator mirrors. To avoid destruction of the outcoupling mirror, a folded three-mirror instead of a two-mirror cavity was tried, resulting in nearly the same output power.