[7p-C24-1~20] 16.1 Fundamental properties, evaluation, process and devices in disordered materials

▲ [7p-C24-16] Al co-doping influence on photo induce absorption of Mg doped silica glasses

〇Edson Haruhico Sekiya¹, Tomoya Okazaki¹, Kazuya Saito¹ (1.Toyota Tech. Inst.)

Keywords:silica glass, photodarkening, Magnesium

Since the great development of Yb doped fiber lasers (YDFL) emitting around 1µm with output power in kW order, industrial applications, such as steel and aluminum cutting/soldering are quickly increasing. To extent the fiber laser application for others metallic materials, it is desirable to shorten the lasing emitting wavelength to visible range. Another big issue related to YDFL is the photodarkening (PD) phenomenon, which diminishes the laser performance due to the formation of defects when the laser is operating at high power density. Recently it was reported an improvement in the PD resistance due to Mg doping but showing few details. In our previous work, it was showed that Mg doping forms clusters into silica glass, which can be minimized by co-doping with Al. So, in this work more systematic Mg co-doped with Al preforms were prepared and characterized. It was observed that the photo induce absorption (PIA) intensity induced by X-ray irradiation, increases with the increase of Al concentration, with a pronounced band around 400nm. Photoluminescence measurements present an emission band around 520nm with excitation bands around 380 and 420nm in these Mg doped samples after X-ray irradiation. According the ESR spectra measured at room temperature, SiE’ defect was identified in all samples after 180min of X-ray irradiation. Al-OHC also can be identified in Al doped samples. Others characterization details and results will be presented to better understanding the Mg PIA.