Near-infrared and Green Light Emission Spectroscopic Characteristics of Er3+ Doped Alumina–phosphate Glasses

Trivalent erbium ions doped (48 – x) AlPO4 + 15K2O + 12MgF + 20Na2O + 5NaF + xEr2O3 glass samples have been prepared utilizing the melt-quench process and studied to understand the efficacy of Er3+ ions content on physical, structural and luminescence attributes of host glass. The functional groups of the glass structure such as metaphosphate, orthophosphate and pyrophosphate have been elucidated through Fourier Transform Infrared (FTIR) spectroscopic investigation. The least-square approach was used to calculate the Judd–Ofelt parameter from the oscillator strength of the Er3+ ion transitions. The luminescence emission data captured in the visible and near-infrared (NIR) province using 380 and 980 nm excitation wavelengths. The up-conversion (recorded at the excitation at 980 nm) of 0.5 Er glass exhibited emission at 664, 550 and 488 nm wavelengths. The decay plots of the studied glass specimens were measured at 980 nm excitation. The McCumber (MC) theory has been implemented to calculate the gain coefficient of the 0.5 Er glass and flat gain curve was drawn for S-band, C-band and L-band. The attributes for optical amplification were ascertained, including the quality factor (0.85), branching ratio (1), stimulated emission cross-section (1.3 × 10–20 cm2), gain bandwidth (1.26 × 10–25 cm3) and optical gain (0.394 × 10–23 cm2 s) for 0.5 Er glass. The yellowish green light emission ability of the 0.5 Er glass after 980 nm excitation evident through CIE co-ordinates position (x 0.36, y 0.58) at 1931 CIE chromaticity diagram. The spectroscopic and luminescence results endorse that the alumino–phosphate glass specimens loaded with 0.5 mol