Photoluminescence features of Ho3+ ion doped PbO–Bi2O3 borophosphate glass systems

Spectroscopic and physical properties of Ho3+ doped multi-component glass systems in varying molar compositions of xBi2O3–(50−x) PbO–25MgHPO4–24B2O3–1Ho2O3 (where x=10, 20, 30, and 40) have been investigated. Optical absorption spectra have been used to determine Racah coefficients (E1, E2 and E3), Slater Condon parameters (F2, F4 and F6), spin–orbit coupling parameters (ξ4f), and configuration interaction parameters (α and β). The ratios of E1/E3 and E2/E3 do not deviate much from the hydrogenic ratios. Optical basicity of the glasses is estimated. The Judd–Ofelt parameters (Ω2, Ω4 and Ω6) were computed from the intensities of the energy levels. The radiative lifetimes (τR), branching ratios (β) and absorption cross sections (σa) were evaluated for the lasing levels 5I8→5G6, 5F2, 5F3, 5F4, 5F5, 5I6, and 5I7. The emission cross sections (σe) for the significant lasing transitions 5F4→5I8, 5F5→5I8 and 5S2→5I7 evaluated from the photoluminescence spectra are reported. The lasing potencies estimated for all the glasses under study indicate lasing action in the cw as well as in pulsed regime.