Er3+/Dy3+ codoped B2O3-TeO2-PbO-ZnO-Li2O-Na2O glasses: Optical absorption and fluorescence features study for visible and near-infrared fiber laser applications

Using melt quenching method, singly Er3+, Dy3+-doped and Er3+/Dy3+-codoped multicomponent borotellurite glasses in the composition (50-x-y) B2O3-10 TeO2-10 PbO-10 ZnO-10 Li2O-10 Na2O-(x) Er2O3- (y) 0.5 Dy2O3 ((x=0.5, 1.0; y=0); (x=0; y=0.5, 1.0); and (x=0.5; y=0.5, 1.0; x=1.0; y=0.5, 1.0)) (mol%) were synthesized. For the fabricated samples, optical absorption, photoluminescence excitation (PLE), photoluminescence (PL), near-infrared (NIR) fluorescence and decay lifetime measurements have been performed. For singly Er3+ and Dy3+-doped samples, Judd-Ofelt (J-O) parameters, Ωt, were calculated following the absorption spectra and the derived Ωt parameters are utilized to predict respective radiative features for these glasses. The PL spectra of the Er3+ and Dy3+ singly doped glasses, excited at 378 nm (Er3+: 4I15/2 → 4G11/2) and 350 nm (Dy3+: 6H15/2→4M15/2,6P7/2), show important green and yellow emission bands at wavelengths 554 nm (Er3+: 4S3/2→4I15/2) and at 574 nm (Dy3+: 4F9/2→6H13/2), respectively. The PL decay curves for Er3+: 4S3/2 level and Dy3+: 4F9/2 level follow single exponential, and non-exponential nature, respectively, for the singly Er3+ and Dy3+-doped samples. For singly 1.0 mol% Er3+ and 0.5 mol% Dy3+-doped samples, the evaluated stimulated emission cross-sections (σPE) for the transitions at λem. = 0550 nm, and 574 nm are equal to 20.923×10-20 cm2 and 0. 526×10-20 cm2, while the gain bandwidths are 3.975×10-25 cm3 and 0.789×10-26 cm3, respectively. For all the Er3+-containing glasses, a broad NIR emission band centered at 1.532 μm (4I13/2→4I15/2) is noticed under both 808 and 980 nm laser diode (LD) excitations, whereas the singly 1.0 mol% Er3+-doped sample shows the highest NIR emission intensity with a full-width at half maximum (FWHM) equal to ~69 and 62 nm, respectively, at these pumping wavelengths. Moreover, the calculated highest (σPE) of 1532 nm NIR emission when pumped by 980 nm is 2.669×10-20 cm2 and gain per unit length is 1.06×10-23 cm2s, for singly 1.0 mol% Er3+-doped glass. Additionally, for Er3+/Dy3+-codoped samples, with the decrement of Er3+: NIR emissions, energy transfer (ET) from Er3+→Dy3+ ions is identified upon both 808 and 980 nm LD pumping. For all Er3+/Dy3+-codoped glasses, the Er3+: 4I13/2 level decay time decreased with increasing Dy2O3 content and the NIR fluorescence decay curves exhibit single exponential nature. Under 980 nm excitation, the computed energy transfer efficiency (ηET) from Er3+: 4I13/2 to Dy3+: 6H11/2 level is 22.9% for the 1.0 Er3+/0.5 Dy3+ (mol%)-codoped glass. Under 808 and 980 nm pumping, the mechanism of the ET processes between Er3+ and Dy3+ ions was discussed in detail. Further, for 1.0 mol% Er3+ singly doped sample, a theoretical gain coefficient value of 17.01 dB/cm is obtained with an excited Er3+ ion fractional factor of 0.6. Following the explored visible and NIR optical results, the synthesized glasses might be useful for visible and NIR fiber lasers application.

Actions (login required)

View Item