Studies on near infrared emission of Yb3+ ions in a SeO2 based glass system

SeO₂ based glasses of the composition 39 PbO–(60-x) B₂O₃– xSeO₂:1.0 Yb₂O₃ (with 10 ≤ x ≤ 50) was synthesized. Analysis of the results of structural studies of the samples revealed that the glass network consists of [SeO₄]²⁻ and [SeO₃]²⁻ units; the studies further indicated an increasing fraction of [SeO₃]²⁻ units and decreasing concentration of [SeO₄]²⁻ groups with increase of SeO₂ content. Optical Absorption (OA) and photoluminescence (PL) spectra have exhibited bands due to ²F_7/2 → ²F_5/2 and ²F_5/2 → ²F_7/2 transitions, respectively. Evaluated absorption and emission cross-sections and lifetime of the excited state of Yb³⁺ ions exhibited an increase with increase of SeO₂ content. Results of PL studies indicated nearly fourfold increase of PL output with increase of SeO₂ content up to 50%. Such increase is attributed to the increased concentration of isolated [SeO₃]^2- pyramidal groups. Overall, the rise of SeO₂ content in Yb³⁺ doped PbO–B₂O₃–SeO₂ glass system facilitated the increase of PL emission of Yb³⁺ ions largely.