Diode-pumped continuous-wave and passively mode-locked Yb:GSO laser

We report on both continuous-wave and passively mode-locked laser actions of a new ytterbium-doped laser crystal Yb:Gd₂SiO₅ (Yb:GSO) under high-power diode-end-pumping. Due to the anisotropic and compact crystal structure, Yb:GSO exhibits a large manifold splitting of Yb³⁺ ions, and a Yb:GSO laser can be operated efficiently with negligible reabsorption losses at emission wavelengths. In the continuous-wave operation, a Yb:GSO laser was operated with a slope efficiency of 49% near 1094 nm-the longest laser wavelength achieved for Yb³⁺ lasers. Passive mode locking was obtained with a semiconductor saturable-absorber mirror. At a pump power of 6. 23 W, a maximum average output power of 638 mW was obtained with the repetition rate of 145.5 MHz.