Investigation of new potential erbium/promethium Co-doped aluminum tellurite glass in active optical materials

Abstract

The possibility of using trivalent erbium/promethium as the active ion in tellurite glass was achieved. Tellurite glass doped with ZnO–Al₂O₃–Pm₂O₃–Er₂O₃ synthesized by the melt-quenching technique. Glasses with varying Er₂O₃ doped concentrations have been produced in the temperature range of 900 °C. The glassy nature of the synthesized samples is verified by the X-ray diffraction (XRD) pattern. Furthermore, to study the synthesized glasses' spectroscopic properties, the absorption spectra are recorded in the range of 200 nm–1800 nm. The spectroscopic properties of the Er³⁺/Pm³⁺ co-doped ions were measured by the Judd-Ofelt theory. The maximum calculated values of Ω_λ (λ = 2,4,6) are 6.5712, 2.29534 and 2.91274 for TZEAP2 glasses. The highest value of spectroscopic quality factor 1.3921 is obtained for the sample TZEAP1. The Judd Ofelt parameter for all the prepared glass samples are follows the trends Ω₂>Ω₄< Ω₆. Three emission bands were detected in the visible region for the Er³⁺/Pm³⁺ ions doped to tellurite glass under the excitation of at 375 nm. These bands were at approximately around 470 nm, 500 nm and 550 nm from ²F_5/2 → ⁴I_15/2, ²H_11/2 → ⁴I_15/2 and ⁴S_3/2 → ⁴I_15/2 radiative transition, respectively. The highest measured cross sections for the green visible transitions ⁴S_3/2 → ⁴I_15/2 are 1.05X10⁻²⁰ cm². The radiative lifetime is also calculated for different Er³⁺ concentrations. The radiative lifetime of the ⁴S_3/2 → ⁴I_15/2 transition increased with an increase in the Er³⁺ concentration. A single exponential decay with a maximum lifetime of 1.71396 msec is detected for the TZEAP4 samples.