Photoluminescence properties of Sm3+-doped SFB glasses for efficient visible lasers

The photoluminescence properties of different concentrations of Sm3+ ions doped sodium fluoroborate (SFB) glasses of composition Na2O–LaF3–CaF2–AlF3–B2O3–SmF3 have been investigated. The energy level analysis is carried out using free-ion Hamiltonian model. The Judd–Ofelt intensity parameters are used to evaluate the laser characteristic parameters such as spontaneous transition probability, radiative lifetime and fluorescence branching ratio for 4G5/2 → 6HJ (J = 5/2, 7/2, 9/2 and 11/2) emission transitions of Sm3+ ion. The principal photoluminescence transitions of interest are identified by recording the emission spectra for different Sm3+ ion concentrations and measuring their emission cross-sections, integrated absorption cross-sections and optical gain parameters. The decay profiles from the 4G7/2 excited manifold state to its lower lying energy levels have been recorded by monitoring the excitation and emission wavelengths at 402 and 600 nm, respectively. The dependence of effective fluorescence lifetime on the Sm3+ concentration is also discussed.