A new saturable absorber <i>Q</i> switch for 1.54-μm Er:glass lasers is presented. The saturable absorber is a transparent glass ceramic that contains magnesium–aluminum spinel nanocrystallites doped with tetrahedrally coordinated Co<sup>2+</sup> ions. We obtained <i>Q</i>-switched pulses of up to 5.5 mJ in energy and 80 ns in duration at 1.54 μm. The relaxation time of <sup>4</sup><i>A</i><sub>2</sub> →<sup>4</sup><i>T</i><sub>1</sub>(<sup>4</sup><i>F</i>) transition bleaching was measured to be (450 ∓ 150) ns. Ground-state and excited-state absorption cross sections at 1.54-μm wavelength were estimated to be (3.2 ∓ 0.4) × 10<sup>−19</sup> cm<sup>2</sup> and (5.0 ∓ 0.6) × 10<sup>−20</sup> cm<sup>2</sup>, respectively.
© 2001 Optical Society of America
Alexander M. Malyarevich, Igor A. Denisov, Konstantin V. Yumashev, Olga S. Dymshits, Alexander A. Zhilin, and Uk Kang, "Cobalt-Doped Transparent Glass Ceramic as a Saturable Absorber Q Switch for Erbium:Glass Lasers," Appl. Opt. 40, 4322-4325 (2001)