Optical properties and energy transfer processes of Ho3+/Er3+- codoped fluorotellurite glass under 1550 nm excitation for 2.0 μm applications

This paper investigates 2.0 μm emission properties and energy transfer processes in the Er3+/Ho3+ codoped fluorotellurite glass. The measured absorption spectra demonstrate that the codoped sample can be pumped by 1550 nm excitation efficiently. Judd-Ofelt and radiative parameters are calculated and discussed. Intensive 2.0 μm emission originating from Ho3+: 5I7→5I8 transition is observed and a long lifetime (11 ms) of the 5I7 level is measured when Ho3+ ions are sensitized by Er3+ ions. Meanwhile, the upconversion spectra of the Er3+ singly and codoped samples are obtained and the energy transfer processes of the two ions is discussed based on the change of the upconversion emissions. The microscopic interaction parameters of the phonon-assisted (Er3+: 4I13/2→Ho3+:5I7) process are calculated and the microparameter reaches as high as 10.1 × 10−41 cm6/s. Hence, these results indicate that this Ho3+/Er3+ codoped fluorotellurite glass will be a suitable material for developing solid state laser around 2.0 μm.