Energy transfer up-conversion in Tm3 -doped silica fiber

Abstract

A study of the mechanisms responsible for the infra-red to near infra-red up-conversion in Tm3+-doped silica fibers is presented. Up-conversion luminescence was observed from the 3H4 level of Tm 3+ under 1586 nm pumping into the 3F4 level. The quadratic dependence of the up-conversion luminescence at 800 nm on the 1800 nm luminescence from the 3F4 level confirms that the 3H4 level is populated by a two photon process. Two possible processes are proposed as mechanisms responsible for the up-conversion: excited state absorption and energy transfer up-conversion. The decay characteristics of the luminescence from the 3H4 level were studied under direct and indirect pumping at 786 and 1586 nm, r..