Intense 2.0 μm emission properties and energy transfer of Ho3+/Tm3+/Yb3+ doped fluorophosphate glasses

Intense 2.0 mu m emission has been obtained from Ho3+/Tm3+/Yb3+ triply doped fluorophosphate glass pumped by a conventional 980 nm laser diode. The spectroscopic properties and energy transfer mechanisms between Ho3+, Tm3+ and Yb3+ are analyzed. Based on the absorption spectra, the Judd-Ofelt parameters, radiation emission rates, radiative lifetime and branching ratios of Ho3+ ions are calculated. It is also found that the 2.0 mu m emission of Ho3+ can be greatly enhanced under the excitation at 980 nm by incorporating Tm3+ and Yb3+ simultaneously. Additionally, the microparameters of the energy transfer processes are quantitatively analyzed. The energy transfer coefficient from Yb3+ to acceptors and from Tm3+ to Ho3+ can reach as high as 13.14 x 10(-40) cm(6)/s and 23.39 x 10(-40) cm(6)/s, respectively. This Ho3+/Tm3+/Yb3+ doped fluorophosphate glass possessing high energy transfer coefficient and excellent thermal stability is a promising candidate for efficient 2.0 mu m laser. (C) 2011 American Institute of Physics. [doi:10.1063/1.3611390]