Effect of Si doping on near-infrared emission and energy transfer of Bismuth in silicate glasses

We have studied the effects of Si doping on the near infrared (NIR) luminescence observed in low Bi doped ( 0.1 mol% ) glasses and the energy transfer from Yb³⁺ to Bi. The broadband near infrared can only be observed when Si is introduced in the Bi-doped glass. The origin of this fluorescence can be attributed to Bi ions at low valence. Efficient energy transfer from Yb³⁺ to Bi NIR active ions is achieved by co-doping of Si. There is an increment of about ~ 29 times of the emission intensity from Bi-related active center as the Yb³⁺ concentration varies from 0 to 2.0 mol% and the amount of Si is 0.05 mol% under 980 nm excitation. The possible mechanism of energy transfer from Yb³⁺ to Bi is also discussed.