Thermal stability and Judd-Ofelt analysis of optical properties of Sm3+-doped sodium tellurite glasses

Abstract

Series of glasses based on (70-x) TeO2 – 20Na2O – xSm2O3 (x=0, 0.3, 0.6, 1, 1.2, 1.5 mol%) have been prepared using melt-quenching technique. The nature of the glass has been confirmed using X-ray diffraction; it is found that the glass samples are amorphous in nature. The thermal stability of the glass has been determined by means of Differential Thermal Analysis (DTA). From the DTA curve, the glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) have been identified and thermal stability is also calculated. The absorption properties of these samples are obtained by using UV-Visible-NIR spectrometer, the recorded absorption spectra exhibit nine absorption transition bands peaks corresponding to the transitions from ground level 6H5/2→6P3/2, 4I11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2. The emission characteristic of this glass is characterized using Photoluminescence (PL) spectroscopy at excited wavelength 404 nm, the emission spectra consisted of four emission bands at 561.95 nm, 598.69 nm, 643.77 nm and 704.56 nm which were assigned as a transition 4G5/2→6H5/2, 6H7/2, 6H9/2 and 6H11/2 respectively. From f-f intensity model the experimental oscillator strengths, fexp and theoretical oscillator strength fcal were calculated. Using Judd-Ofelt theory and fit process of least square, the phenomenological intensity parameters Ωλ (λ=2,4,6) were obtained, In order to evaluate potential applications of Sm3+ ions in telluride glasses, the spectroscopic parameters: transition probability AR, branching ratio Br, radiative life time τr, emission pick cross section σλ for each band were calculated. The comparative studies with other Sm3+ doped different glasses showed that present glasses could be a potential candidate for lasers.