Structural and spectroscopic studies of Er 3+ in different fluorophosphate glasses for green laser and fibre amplifier operations

Erbium activated fluorophosphate glasses were synthesized with conceived characteristic combination, 59.5NH 4 H 2 PO 4 +15ZnO+15BaF 2 +10X+0.5Er 2 O 3 (X = LiF, NaF, CaF 2 , SrF 2 , AlF 3 ) by melt quenching route. Based on the mass densities, and refractive indices, other physical properties i.e., dielectric constant ( ε ), reflection losses, molar refraction, internuclear distance and molar volume are determined. XRD has confirmed the non-crystalline character of the prepared glass samples. FTIR, FT-Raman have been employed to study the structural characteristics. Various radiative properties have been inferred through optical absorption measurements by standard Judd–Ofelt procedure. By excitation at 379 nm, all the glass hosts doped with constant concentration 0.5 mole% of Er 3+ have yielded intense green emission peak due to the transition 4 S 3/2 → 4 I 15/2 at 545 nm. Characteristic emission transition 4 I 13/2 → 4 I 15/2 at wavelength 1.53 μ m has been studied extensively. Particularly the parameters related to that transition namely, stimulated emission cross-sections ( σ e ) and optical gains (G) are calculated from emission spectra. Among all the fluorophosphate glasses, the one which has shown higher σ e , and G values is sodium fluorophosphate (NFPE) glass. It is recommended for optical fiber amplification and NIR laser usage.