Optical and erbium ion concentration correlation in lithium magnesium borate glass

Abstract

Tuning the optical response of lithium magnesium borate glass via controlled doping of rare earth ions is the key issue in photonic devices. Glasses with composition 30Li2O-(60-x)B2O3-10MgO-xEr2O3, where 0 ≤ x ≤ 1 are prepared by conventional melt-quenching technique. The X-ray diffraction (XRD) pattern confirms the amorphous nature of all samples. Fourier transform infrared (FTIR) spectra reveal the presence of BO3 and BO4 local structure unit. The physical parameters, such as the direct and indirect optical energy band gap, oscillator strength, refractive index, ion concentration, Polaron radius, molar volume and inter-nuclear distance are calculated and analyzed. The room temperature UV-vis-IR spectra comprised of ten absorption bands centered at 1523, 973, 796, 650, 550, 522, 486, 447, 406, 373 nm corresponding to the transitions from the ground state to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 4S3/2, 2H11/2, 4F7/2, (4F5/2 + 4F3/2), 2G(1)9/2, 4G11/2 excited states, respectively. The peak evidenced at 522 nm is due to hypersensitive transition. The up-conversion spectra exhibits three emission peaks centered at 509, 547 and 656 nm. All the emission bands (green and red) at 0.5 mol% of Er3+ shows a significant enhancement in the intensity attributed to the energy transfer from Mg2+ to the Er3+ ion. Our results suggest that these glasses can be nominated for solid state lasers.