Processes of energy transfer in Er3+-Tm3+ co-doped tellurite glasses has permitted to obtain an expanding broadband emission in the near-infrared region covering the bands S, C+L and U of the optical telecommunications and extending up to the 1700-1900 nm range under excitation by a 976 nm laser diode. This widening of the emission band is achieved through an integrated emission, where the Er3+ ions act as donor and the Tm3+ ions as acceptor following the route (Er3+) 4I11/2→(Tm3+)3H5, (Er3+)4I13/2→(Tm3+) 3H4 and (Er3+)4I 13/2→(Tm3+)3F4. The relative intensity emission and lifetime of the 4I13/2→ 4I15/2 transition of the Er3+ ions decrease with increasing the Tm3+ concentration. Besides, high Tm3+ concentrations produce an emission quenching for the 3H 4→3F4 and 3F 4→3H6 radiative transitions, due to cross-relaxation between Tm3+ ions. These effects are studied by means of probability and quantum yield of the energy transfer. The most intense and widest emission band is measured in the glass co-doped with 0.075 and 1 mol% of Tm2O3 and Er2O3, respectively.
Bibliographical noteFunding Information:
This work was supported by the Brazilian agencies FAPESP – Processes : 2009/08978-4 and 2011/21293-0 , CNPq through the INOF/CEPOF (Instituto Nacional de Óptica e Fotônica and Centro de Pesquisa em Óptica e Fotônica – São Paulo – Brasil) and the Canadian Excellence Research Chair program (CERC) .
- Broadband emission
- Energy transfer
- Optical properties
- Tellurite glass