Optical properties of Sm³⁺ doped in CaO-Al<inf>2</inf>O<inf>3</inf>-Na<inf>2</inf>O-BaO-B<inf>2</inf>O<inf>3</inf> glasses for under-sea optical device applications

Abstract

23CaO-10Al2O3-10Na2O-6BaO-(51-X)B2O3-XSm2O3 where, X = 0.0 (S0), 0.1(S1), 0.3(S2), 0.5(S3), 1.0(S4) glasses was fabricated by melt-quench technique. The characterization for the glass was performed by the standard techniques of XRD, FTIR, optical absorption, and fluorescence spectra. Physical properties such as dielectric constant, rare earth ion (Sm3+) concentration, polaron radius, interionic distance, field strength, average boron-boron interaction, molar refractivity, molar polarizability, metallization criteria, molar cation polarizability, electronic oxide ion polarizability, optical basicity, theoretical optical basicity, interaction parameter was determined. FTIR spectra confirm the signature borate vibrations. Judd-Ofelt (JO) analysis was evaluated and JO parameters show Ω2 > Ω4 > Ω6 trend. Glasses with 0.1 and 0.3 mol% Sm2O3 had the greatest value of Ω2, due to ligand field asymmetry and rare earth oxygen (Sm-O) covalent bonds at rare-earth ion sites. Photoluminescence spectra reveal three emission peaks originating from 565, 602, and 649 nm corresponding to 4G5/2→6H5/2, 6H7/2, and 6H9/2 respectively. Radiative properties such as stimulated emission cross-sections (σ) and branching ratios (β) was calculated and show higher value for 0.3 mol% Sm2O3 sample which is compared with other glasses. At 0.3 mol% of Sm2O3 content, concentration quenching was observed and attributed to transfer of energy via cross-relaxation channels within Sm3+ ions. The observed radiative properties for the prepared glass system show that they are efficient for developing under-sea optical device applications in the reddish-orange spectral region. The chromaticity coordinates were evaluated for the glasses. The evaluated (x,y) coordinates are observed to be found in the orange-red region of the CIE 1931 chromaticity diagram. The CCT values were obtained from CIE (x,y) coordinates.