Spectroscopic properties of Ho3+/Yb3+ codoped lanthanum aluminum germanate glasses with efficient energy transfer

Abstract

Ho 3 + / Yb 3 + codoped lanthanum aluminum germanate glasses are prepared simply by melt-quenching method. The 2 μm emission characteristic and energy transfer from Yb3+ to Ho3+ upon excitation of a conventional 980 nm laser diode is investigated and the energy transfer efficiency is as high as 83%. The spectroscopic parameters are calculated based on Judd–Ofelt (J-O) theory, the intensity parameters Ω2, Ω4, and Ω6 are 4.44, 1.92, and 1.11×10−20 cm2, respectively. The transition probabilities and branching ratios are also estimated by using the J-O parameters. Beer–Lambert and Fuchtbauer–Ladenburg theories are applied to calculate the absorption, emission, and gain cross sections of I57→I58 transition.