Energy transfer from Cr to Nd in substitutional crystal Y3GaxAl5-x O12 codoped with Nd and Cr

Garnet crystals codoped with Nd3+ and Cr3+ ions are a candidate for solar-pumped laser materials. Substitutional disordered crystals Y3GaxAl5-xO12 were prepared to improve the pumping efficiency of Nd3+ luminescence and energy transfer from Cr3+ to Nd3+ ions. The substitutional disordered crystal host produced inhomogeneous broadening of the Nd3+ and Cr3+ optical spectra. Enhancement of overlapping between the Cr3+ absorption bands and the solar spectrum, and between the Cr3+ luminescence bands and the Nd3+ absorption lines led to the increases of the pumping efficiency and the energy transfer rates, respectively. The excitation spectrum of the Nd3+ luminescence, the nonexponential decay curves of the Cr3+ luminescence, and the quantum yields of the Cr3+ and Nd3+ luminescence have given evidence on the energy transfer from Cr3+ to Nd3+ ions.