Phonon assisted effective non-resonant energy transfer based 1 μm luminescence from Nd3+-Yb3+ codoped zinc-boro-bismuthate glasses

► Efficient Nd3+ sensitized broadband Yb3+ emission at 1 μm. ► Effective host phonons assistance in Nd3+→Yb3+ non-resonant energy transfer. ► Energy transfer by hopping mechanism among donor ions. ► Optimum acceptor (Yb2O3) concentration is 1 mol% for strong 1 μm emission.