Femtosecond laser induced space-selective precipitation of Cr3+-doped ZnAl2O4 crystal in glass

We report the space-selective precipitation of Cr3+-doped ZnAl2O4 crystals in aluminosilicate glass by femtosecond (fs) laser irradiation. The precipitation of ZnAl2O4 crystal was confirmed by x-ray diffraction (XRD), Raman spectra and transmission electron microscopy (TEM), and the incorporation of octahedron Cr3+ in ZnAl2O4 crystal was testified by electron paramagnetic resonance (EPR) and luminescence spectra. The laser irradiated area shows greatly enhanced luminescence due to Cr3+ transitions. This method is promising for waveguide laser and three dimensional (3D) optical storage.