Spectroscopic analysis of Tm3+:NaLa(MoO4)2

Abstract

Absorption spectra of trivalent thulium (Tm3+, 4f12) doped double molybdate NaLa(MoO4)2 (NLM) are reported between 370 and 2000 nm at approximately 16 K. Laser-excited fluorescence spectra obtained at 4.2 K from multiplet manifolds 1G4 and 3H4 to manifolds 3F4 and the ground state 3H6 are also reported. The observed spectra are broad in this disordered host as compared with the spectra observed for Tm3+:YAG (yttrium aluminum garnet). The observed crystal field splitting of the multiplet manifolds in Tm3+:NLM is in reasonable agreement with the calculated splitting based on smoothed crystal field parameters obtained from an analysis of Nd3+:NLM and Er3+:NLM. The smaller crystal field splitting in Tm3+:NLM as compared with Tm3+:YAG may discourage cross-relaxation from the 3H4 to the 3F4 manifold in this host. This in turn may favor laser operation on the 3H4→3F4 transitions over the 3F4→3H6 transitions.