EVALUATION OF ABSORPTION AND EMISSION PROPERTIES OF YB-3+ DOPED CRYSTALS FOR LASER APPLICATIONS

The emission and absorption properties of numerous host crystals doped with Yb3+ ions have been studied. The hosts which have been selected present a variety of crystal field environments for the ytterbium ion, including fluoride and oxide crystals with six-, seven-, eight-, nine - and twelvefold coordinated substitutional sites. The crystal compoun ds include LiYF4, LaF3, SrF2, BaF2, KCaF3, KY3F10, Rb2NaYF6, BaY2F8, Y 2SiO5, Y3Al5O12, YAlO3, LuPO4, Ca5(PO4)3F, LiYO2, and ScBO3. Spectral determinations have been made of the resonant absorption and emission cross sections between 850 and 1100 nm, and the emission decay times o f the upper laser level have been measured. The emission cross section s have been evaluated using the absorption cross section and principle of reciprocity, and again using the Fuchtbauer-Ladenburg formula. Agr eement between the two methods is within 20% for most materials. The r esults of this survey are discussed in the framework of requirements f or an effective diode-pumped Yb3+ laser system. Ca5(PO4)3F:Yb is predi cted to exhibit the most useful laser properties and is expected to be superior to Y3Al5O12:Yb in many key spectroscopic parameter values.