Broadband Visible Light Emission From Nominally Undoped and <inline-formula> <tex-math notation="TeX">$\hbox{Cr}^{3+}$</tex-math></inline-formula> Doped Garnet Nanopowders

Abstract

Synthetic garnet nanopowders of Y3Al5O12 (YAG) and Gd3Ga5O12 (GGG) were produced, and the occurrence of a broadband bright visible emission by nominally undoped YAG and GGG and Cr3+ doped GGG, depending on the environment pressure, as well as exciting on the pumping power, was demonstrated. The results indicate that high-intensity infrared laser irradiation in samples not only leads to heating (melting effects) but also produces visible broadband emission. Low pressure of the powders' environment favors the white light emission by lowering the threshold pumping power. A hypothesis on the nature of the emission is presented.