Fabrication and properties of Yb-doped silica glass films for laser waveguide application

This paper describes the fabrication of Yb3+-doped silica glass films prepared by RF magnetron sputtering for laser applications. The deposition parameters and the subsequent thermal treatments were accurately adjusted to obtain layers with appropriate structural characteristics (flat surface, homogeneity) and optical properties (refractive index, absorption and fluorescence emission). The structural properties of the deposited films have been investigated by infra-red absorption spectroscopy and atomic force microscopy, while the layer composition was determined by an Energy Dispersive X-ray spectrometer. The optical properties of the films have been investigated by time resolved photoluminescence, providing relevant parameters such as the Yb3+ fluorescence lifetime that governs the high pump energy storage and laser efficiency. The obtained values of the lifetime are scaling from 50 to 610 μs, and therefore are comparable to those usually reported for Yb3+-doped silica glass fibers.