A robust solid-state saturable absorber was developed with cobalt-ion-doped tellurite glasses that has a broad saturable-absorption band in the near-infrared. A nonlinear optical absorber was measured by the Z -scan technique. Numerically fitting the Z -scan experimental data yields excited-state absorption cross sections at a 1064-nm laser wavelength of σ<sub>es</sub>=1.45×10<sup>-20</sup> and σ<sub>es</sub>=1.15×10<sup>-20</sup> cm<sup>2</sup> for 1.0- and 2.5-at. % Co<sup>2+</sup> -doped glasses, respectively.
© 2003 Optical Society of America
E Wu, Hao Chen, Zhenrong Sun, and Heping Zeng, "Broadband saturable absorber with cobalt-doped tellurite glasses," Opt. Lett. 28, 1692-1694 (2003)