Infrared laser performance and self-frequency doubling of Nd3+:Ca4GdO(BO3) (3)(Nd:GdCOB)

Gadolinium calcium oxoborate, Ca4GdO(BO3)(3) (GdCOB), is an efficient nonlinear berate crystal presenting suitable sites for activator ions. Nd3+ doped GdCOB has been investigated as a new laser crystal in order to develop a self-frequency doubling material. Large and good optical quality crystals of Nd:GdCOB have been grown from the melt. Nd3+ optical properties were studied via Judd-Ofelt analysis. Nd3+ polarized absorption and emission cross sections were measured at room temperature. Stark levels of Nd3+ 4Lj manifolds in GdCOB are given. Nd:GdCOB laser has been demonstrated, with a cw Ti:sapphire pump source, for several Nd3+ concentrations. The crystal was shown to lase along its three crystallophysic axes. The best slope efficiency is 45% for the fundamental laser output at 1.060 mu m. According to the infrared laser output polarization, configuration of Nd:GdCOB crystals, for type I self-frequency doubling in ZX and XY principal planes, were investigated. A 0.530 mu m green laser was observed by self-frequency doubling. Linear and nonlinear optical properties of Nd:GdCOB are compared to those of NYAB in the prospect of self-frequency doubling applications. (C) 1997 Elsevier Science B.V.