Fluoride crystals: materials for near-infrared solid state lasers

In this work we present an overview of the best 2μm laser results obtained in Tm-doped fluoride hosts LiYF 4 (YLF), LiLuF 4 (LLF) and BaY 2 F 8 (BYF) and we report on the growth, spectroscopy and first laser test emission of a novel mixed material BaYLuF 8 (BYLF), interesting as a variant of BYF material with a partial substitution of Y 3+ ions by Lu 3+ . The novel host is interesting mainly because indications are that the mixed crystal would be sturdier than BYF. The addition of Lutetium would improve the thermo-mechanical properties going into the direction of high power applications, as suggest from works on YLF and its isomorph LLF. A detailed description of Czochralski growth of fluoride laser materials is provided, focusing on the growth parameters of the novel BYLF:Tm 3+ 12% material grown. With regard of spectroscopy analysis, we report on the results obtained with BYLF host. Detailed absorption, fluorescence and lifetime measurements have been performed focusing on the 3 H 4 and 3 F 4 manifolds, the pumping and upper laser level. Moreover diode pumped CW laser emission at 2 μm has been achieved in BYLF: Tm 3+ 12% sample obtaining a slope efficiency of about 28% with respect to the absorbed power.