Effects of alkaline earth ions on the broadband near infrared emissions of Bi doped aluminophosphsilicate glasses

The effects of alkaline earth ions as network modifiers on the broad near infrared (NIR) emission from bismuth doped aluminophosphsilicate glasses were investigated. The results showed the intensity of NIR emission peaked at 1300 nm increased with increase in the radius of alkaline earth ions, while those of NIR emission peaked at 1100 nm and red emission from Bi2+ vary in an opposite tendency. We propose that particular emission performance of Bi result from the abnormal reduction phenomenon of Bi ions by SiO2–P2O5–Al2O3–RO (R = Mg, Ca, Sr, Ba, SPAR) glass hosts, which became effective with the order of MgO–CaO–SrO–BaO. Then the origins of infrared-emitting bismuth centers were discussed according to the effect of alkaline earth ions on the conversion of Bi ions.