Assignments and optical properties of X-ray-induced colour centres in blue and orange radiophotoluminescent silver-activated glasses

We have systematically investigated the origin and optical properties of the X-ray-induced colour centres based on the blue and red radiophotoluminescence (RPL) in a silver-activated phosphate glass. The induced-absorption band was decomposed into six Gaussian bands on the basis of its strong analogy with silver-activated sodium chloride. We have ascribed these bands to Ag0, Ag2+, Ag2+ and other silver ion species by means of optical and thermal measurements such as colour centre formation and dissolution by highly successive femtosecond-pulse irradiation, excited-state lifetime and thermal annealing characteristics. The data confirmed that the blue RPL at 450 nm could be attributed to the 270 and 345 nm bands due to the Ag2+ and Ag0 centres, respectively, and that the orange RPL at 560 nm was associated with the 308 nm band due to the Ag2+ centres.