AbstractThe foremost limitation of an oxide based crystal or glass host to demonstrate mid- infrared emissions is its high phonon energy. It is very difficult to obtain radiative mid-infrared emissions from these hosts which normally relax non-radiatively between closely spaced energy levels of dopant rare earth ions. In this study, an intense mid-infrared emission around 2.9 μm has been perceived from Ho³⁺ ions in Yb³⁺/Ho³⁺ co-doped oxide based tellurite glass system. This emission intensity has increased many folds upon Yb³⁺: 985 nm excitation compared to direct Ho³⁺ excitations due to efficient excited state resonant energy transfer through Yb³⁺: ²F_5/2 → Ho³⁺: ⁵I₅ levels. The effective bandwidth (FWHM) and cross-section (σ_em) of measured emission at 2.9 μm are assessed to be 180 nm and 9.1 × 10⁻²¹ cm² respectively which are comparable to other crystal/glass hosts and even better than ZBLAN fluoride glass host. Hence, this Ho³⁺/Yb³⁺ co-doped oxide glass system has immense potential for the development of solid state mid-infrared laser sources operating at 2.9 μm region.