The effect of P2O5 on the ultra broadband near-infrared luminescence from bismuth-doped SiO2-Al2O3-CaO glass

► P2O5 had inverse effect on the intensity of two broad infrared emissions of Bi ions centered at 1300 and 1100 nm. ► The addition of P2O5 brings out the broadening of full width at half maximum (FWHM) of these two infrared emissions. ► Infrared emissions at 1100 and 1300 nm originate from different valence Bi ion in glasses. ► The inverse effect of P2O5 on the two broad infrared emissions resulted from abnormal reducing process of glass structure.