Spectroscopic investigations of Nd3+-, Er3+-, Er3+/Yb3+-, and Tm3+-ions doped SiO2-Al2O3-CaF2-GdF3 glasses

This paper reports on the absorption, visible and near-infrared luminescence properties of Nd3+, Er3+, Er3+/2Yb(3+), and Tm3+ doped oxyfluoride aluminosilicate glasses. From the measured absorption spectra, Judd-Ofelt (J-O) intensity parameters (Omega(2), Omega(4) and Omega(6)) have been calculated for all the studied ions. Decay lifetime curves were measured for the visible emissions of Er3+ (558 nm, green), and Tm3+ (650 and 795 nm), respectively. The near infrared emission spectrum of Nd3+ doped glass has shown full width at half maximum (FWHM) around 45 nm (for the F-4(3/2) -> I-4(9/2) transition), 45 nm (for the F-4(3/2) -> I-4(11/2) transition), and 60 nm (for the F-4(3/2) -> I-4(13/2) transition), respectively, with 800 nm laser diode (LD) excitation. For Er3+, and Er3+/2Yb(3+) co-doped glasses, the characteristic near infrared emission bands were spectrally centered at 1532 and 1544 nm, respectively, with 980 nm laser diode excitation, exhibiting full width at half maximum around 50 and 90 nm for the erbium I-4(13/2) -> I-4(15/2) transition. The measured maximum decay times of I-4(13/2) -> I-4(15/2) transition (at wavelength 1532 and 1544 nm) are about 5.280 and 5.719 ms for 1Er(3+) and 1Er(3+)/2Yb(3+) (mol%) co-doped glasses, respectively. The maximum stimulated emission cross sections for I-4(13/2) -> I-4(15/2) transition of Er3+ and Er3+/Yb3+ are 10.81 x 10(-21) and 5.723 x 10(-21) cm(2). These glasses with better thermal stability, bright visible emissions and broad near-infrared emissions should have potential applications in broadly tunable laser sources, interesting optical luminescent materials and broadband optical amplification at low-loss telecommunication windows. (C) 2009 Elsevier B.V. All rights reserved.