Research on blue-green luminescence properties and energy transfer in Tm³⁺/Tb³⁺ co-doped TeO₂-GeO₂-Bi₂O₃-BaF₂ glass

Abstract Tm 3+ /Tb 3+ co-doped TeO 2 -GeO 2 -Bi 2 O 3 -BaF 2 glasses were synthesized via high-temperature melt-quenching to achieve blue-green fluorescence emission. Under 808 nm pump excitation, the TGBB2 sample (Tm 2 O 3 :Tb 4 O 7 = 3:8) exhibited balanced emissions at 452 nm (blue, Tm 3+ : 1 G 4 → 3 H 6 ) and 544 nm (green, Tb 3+ : 5 D 4 → 7 F 5 ). With increasing Tb 3+ concentration, green emission intensity increased while blue emission decreased, confirming efficient Tm 3+ →Tb 3+ energy transfer. Key performance metrics for TGBB2 included: a forward energy transfer coefficient of 571.83×10 -40 cm 6 /s (far exceeding the reverse coefficient of 63.12×10 -40 cm 6 /s), an energy transfer efficiency of 99.5%, maximum emission cross-sections of 5.87×10 -21 cm 2 (476 nm, Tm 3+ ) and 3.37×10 -21 cm 2 (486 nm, Tb 3+ ), and corresponding gain coefficients of 2.98 cm -1 and 0.46 cm -1 . These results validate the glass’s low laser threshold, making Tm 3+ /Tb 3+ co-doped tellurite-germanate-bismuthate glass a promising candidate for blue-green laser communication and underwater optical transmission.