文摘
The primary objective of this study is to characterize 1G4 → 3H5 (1.3 μm, which is highly important in telecommunications) and also 3P0 → 3F2 (red emission) spectral lines of Pr3+ ions in lead silicate glasses sensitized with bismuth ions. The intensity of these spectral lines exhibited large amplification (nearly four times) due to co-doping with Bi3+ ions with fixed concentration of Pr3+ ions. Several radiative parameters, e.g., transition probabilities (Aij), branching ratios (β), radiative life times (τ) and quantum efficiencies (η) of these spectral lines were evaluated using modified Judd-Ofelt theory. These parameters exhibited the maximal values when the glasses were codoped with the optimal concentration of Bi2O3 (5.0 mol%). The increasing population of 3P0 and 1G4 levels of Pr3+ ions (with the gradual increase of Bi2O3 concentration up to 5.0 mol%) that caused the amplification of above mentioned emissions occurred: (i) due to the energy transfer from 3P1→1S0 emission transition of Bi3+ ions and (ii) due to the increasing presence of Bi3+ ions in octahedral positions that are predicted to induce structural defects in the glass network. The quantitative analysis of these results together with the kinetic rate equations suggested that the Pr3+ ions doped lead silicate glasses mixed with (about 5.0 mol%) Bi2O3 are highly efficient in producing intense 1.3 μm (1G4 → 3H5) narrow emission. Hence, it is concluded that the optical fibers drawn from the glasses of such compositions are highly useful for the applications in the second telecom window.
