Spectroscopy properties of 'Er POT.3+' in chalcogenide glasses - Vila, L D; Aranha, N; Messaddeq, Younnes; Stucchi, Elizabeth Berwerth; Ribeiro, Sidney J L; Fagundes, D; Nunes, Luiz Antônio de Oliveira (Rare Earths' 2001, 2001)