Recent progress in Cr/sup 4+/ lasers

Summary form only given. This talk first reviews recent results in cw and femtosecond performance of the Cr:forsterite and Cr:YAG lasers. Limitations on the performance of these lasers in terms of excited-state absorption and thermally enhanced nonradiative decay are emphasized. New hosts such as montecellite, YSO, and the scandium garnets are discussed. Diode-pumping experiments are reviewed, and possible reasons why diode pumping has not (yet) been successful are proposed. New laser architectures such as waveguide lasers based on composites of Cr:forsterite nanocrystals in a refractive-index-matched host are described.