Laser oscillation of Nd via energy transfer process from Cr to Nd in substitutional disordered garnet crystals codoped with Nd and Cr

Substitutional disordered garnet crystal hosts such as (Y1-xGdx)3(Al1-yScy)5O12 (YGSAG) produce inhomogeneous broadening of the optical spectra of the dopant, making them good candidates for solar-pumped laser materials. In the case of codoping with Nd and Cr ions, the spectral overlapping between the Cr absorption bands and the solar spectrum and between the Cr emission lines/bands and the Nd absorption lines leads to the increase of the pumping efficiency for the Nd emission. As a consequence of energy transfer from Cr to Nd, the threshold of the Nd laser oscillation is expected to be reduced when compared with that of the single doped Nd crystal. The laser oscillation of the Nd stimulated emission for Nd:Cr:YGSAG has been evaluated using an Ar ion laser, giving evidence of the energy transfer excitation processes involved in the laser output.