SPECTROSCOPIC STUDIES OF RARE EARTH LONS DOPED LITHIUM BISMUTH ALUMINO BOROSILICATE GLASSES FOR PHOTONIC APPLICATIONS

Abstract

Lithium bismuth alumino borosilicate (LiBiAlBSi) glasses were successfully prepared by melt quenching procedure using single and codoped RE ions such as samarium (Sm3+), terbium (Tb3+), europium (Eu3+) and erbium (Er3+). The structural, physical, absorption, photoluminescence (PL), decay spectral profiles and time-dependent PL studies of the prepared glasses have been performed to understand the suitability of these glasses for various photonic applications. The XRD and FT-IR studies are used for structural characterization. XRD patterns were recorded for un-doped and RE-doped glasses and all showed non-appearance of intense sharp peaks which confirms the amorphous nature of our glasses. FT-IR spectrum identified the different functional groups in the un-doped glass. For physical characterization, the density and refractive index of the as-prepared glass have been measured using well-known methods. Various other physical quantities such as dielectric constant, reflection losses, molar refraction, polaron radius, dielectric constant and electronic polarizability were assessed using density and refractive index by the recognized methods available in the literature. From the absorption spectra, the energies of the absorption bands termed oscillator strengths were measured to evaluate the Judd-Ofelt (J-O) parameters using the least square fitting procedure. The J-O parameters and emission spectra were used for finding numerous radiative parameters such as emission cross-section, transition probability, radiative lifetimes, total transition probability, branching ratios, gain bandwidths and optical gain for the noticeable transitions of the RE3+ doped LiBiAlBSi glasses. A Time-dependent PL study showed our glass system has good thermal stability. The aforesaid parameters are very much vital for various photonic applications such as solid-state lasers, white LEDs in solid-state lighting, PV cells and fiber amplifiers. The emission spectra of co-doped Sm3+/Eu3+ LiBiAlBSi glasses obtained the down-conversion ability of the n-UV and blue wavelength photons and ET process found from Sm3+ ions to Eu3+ ions in our glass system. The quantum efficiency of the obtained glasses was evaluated by correlating experimental decay times with radiative lifetimes. Moreover, CIE chromaticity coordinates were assessed to understand the appropriateness of prepared glasses for several visible emission applications.