Optical Absorption and Emission in Rare Earth Heavy Metal Fluoride Glasses
AbstractTrivalent thulium is a 4-level laser system which operates in the 1.47μm spectral region. A tunable amplifier at this wavelength is of great interest since it falls in one of the telecommunication windows. For lasing action to occur the relatively long lived 3F4 lower laser level must be quenched to eliminate the self-terminating behavior of thulium. Rosenblatt et al. co-doped Tm and Th into a ZBLAN host to quench the 3F4 lower laser level.[1] Co-doping with Ho offers the possibility of more efficient laser operation, but it must be established whether Ho can effectively quench the lower level of Tm. This preliminary study indicated appreciable energy transfer occurred from the 3F4 level of Tm to the 5I7 level of Ho which decreased the lower laser level lifetime by as much as two orders of magnitude. The subsequent decay of the Ho ions is an issue requiring further investigation.