Self-absorption and radiation trapping in -doped -based glasses M. Mattarelli, M. Montagna, L. Zampedri, A. Chiasera, M. Ferrari, G. C. Righini, L. M. Fortes, M. C. Gonçalves, L. F. Santos and R. M. Almeida Europhys. Lett., 71 3 (2005) 394-399 Published online: 06 July 2005 DOI: 10.1209/epl/i2005-10092-4