Energy transfer and O'H POT. -' influence on 1.8 'mü'm emission efficiency of 'Tm POT. 3+'/'Yb POT. 3+' co-doped sodium-aluminophosphate glasses - Terra, Idelma Aparecida Alves; de Camargo, Andrea Simone Stucchi; Nunes, Luiz Antônio de Oliveira (International Symposium on Non-Crystalline Solids - ISNCS, 2007)