Infrared-to-visible upconversion in K_5Nd(MoO_4)_4 stoichiometric laser crystal

Abstract

We report the upconversion processes that produce violet, blue, green, orange, and red emissions in K5Nd(MoO4)4 stoichiometric crystal together with the dynamics and spectral properties of the laser emission. The influence of upconversion energy-transfer processes on the energy storage capacity through the reduction of fluorescence lifetimes of the metastable 4F3/2 level is investigated. The experiments were conducted in such a way that the dynamics of the infrared and visible fluorescence was performed under lasing and nonlasing conditions. The dynamics of the upconverted emission shows that both energy-transfer upconversion and excited-state absorption of the laser emission occur. A brief analysis about the polarization properties of the laser emission is presented.