Judd–Ofelt analysis and improvement in thermal stability and optical properties of Er³⁺ doped TeO₂–ZnO–Na₂O–B₂O₃–GeO₂ glasses

Abstract

Er³⁺ doped TeO₂–ZnO–Na₂O–B₂O₃–GeO₂ glasses were elaborated by melt quenching method with powders being immersed in CCl₄ that served as a reagent of dehydration. The structure has been investigated by means of Fourier transform infrared spectroscopy. Differential scanning calorimetry and thermal mechanical analysis determined thermal parameters. It is found that glasses obtained from the present work have high thermal stability against crystallisation. The difference of crystallisation temperature T_x and glass transition temperature T_g is >155°C and the thermal expansion a is in the range of 8·668×10⁻⁶–12·279×10⁻⁶°C⁻¹. The theories of Judd–Ofelt and McCumber are applied to analyse the optical spectra. Intensity parameter Ω_λ (λ = 2, 4 and 6), transition probability A_ed, radiative lifetime τ_i and branching ratio β of the Er³⁺ transitions were obtained. The emission cross-sections σ_emis of Er³⁺:⁴I_13/2→⁴I_15/2 transitions have been calculated. All the above parameters indicate that the properties of Er³⁺ doped TeO₂–ZnO–Na₂O–B₂O₃–GeO₂ glasses have been improved effectively in the present work. The glass can be used as ideal material for optical amplifiers.

Keywords:

• Tellurite glasses
• Er³⁺
• Thermal stability
• Judd–Ofelt analysis
• Optical amplifier