Fabrication of Nd3+, Cr4+ co-doped Gd3Ga5O12 thin film waveguide by two-target pulsed laser deposition

The growth of Nd3+,Cr4+ co-doped gadolinium gallium garnet (Gd3Ga5O12:GGG) (1 1 1) thin films on YAG (1 1 1) substrate has been demonstrated with two-target pulsed laser deposition and post-annealing. The concentrations of Nd and Cr in the co-doped thin film are well controlled by changing respective KrF laser ablation fluence for Nd:GGG and Cr,Ca:GGG sintered targets. The structure of Nd,Cr:GGG thin films on the YAG substrate shows a waveguide structure with high numerical aperture. It is confirmed that the Nd3+ and Cr4+ ions in co-doped films act as the laser active ion and saturable absorber, respectively, at 1.06 μm to be able to be used for monolithic self Q-switched waveguide laser to generate high peak power and short pulse output.