Preparation and characterization of sol-gel derived highly transparent aluminosilicate glass thin films with ultrahigh doping level of Yb3+ ions

A series of highly transparent aluminosilicate glass films with ultrahigh doping level of Yb 3+ ions have been prepared by Sol-Gel method and deposited on transparent silica glass substrates with thickness ranging from 0.901 μm to 1.314 μm and doping level of Yb 3+ ions up to 30 mol%. Each film exhibits a characteristic photoluminsecence spectrum of Yb 3+ ions with a maximum at 975 nm and high transmission in VIS-NIR region. The refractive index for the film has been measured by spectroscopic ellipsometry . AFM images and EPMA cross-sectional images have presented the formation of film surface and cross section respectively and a uniform film formation has been achieved with the composition of 10YbO 1.5 -15AlO 1.5 -75SiO 2 and 20YbO 1.5 -12AlO 1.5 -58SiO 2 . It has been verified that multilayer films get a major improvement in photoluminescence intensity still with high transmission in VIS-NIR region.