Photodarkening mechanisms of Pr3+ singly doped and Pr3+/Ce3+ co-doped silicate glasses and fibers

In this work, we revealed the possible mechanisms of the photodarkening in Pr3+ ions singly doped and Pr3+/Ce3+ co-doped silicate glasses and fibers induced by X-ray and 488-nm laser radiations and studied the role of Ce3+ in increasing radiation resistance in Pr3+-doped silicate glasses and fibers. The absorption, emission, electron paramagnetic resonance (EPR), radiation induced attenuation spectra, and X-ray photoelectron spectroscopy (XPS) of Pr3+ singly doped and Pr3+/Ce3+ co-doped silicate glasses before and after X-ray radiation were measured and analyzed. The fluorescence intensity and photoinduced attenuation of Pr3+ singly doped and Pr3+/Ce3+ co-doped silicate fibers at visible wavelengths pumped by 488-nm laser were measured and analyzed. The influence of Ce3+ ions co-doping on the spectroscopic properties of Pr3+ ions as well as the radiation-induced defects in silicate glasses was studied. Results demonstrate that both X-ray and 488-nm laser radiations will induce photodamage in Pr3+ ions-doped silicate glasses and fibers. Co-doping Ce3+ (by up to 1 mol%) is efficient to suppress the darkening induced by both X-ray and 488-nm laser radiations without influence on the luminescence behavior of Pr3+ ions in silicate glasses and fibers. Our studies demonstrate the promising potential of Pr3+/Ce3+ co-doped silicate glasses for visible lasing applications.