Photochemical reactions of samarium ions in sodium borate glasses irradiated with near-infrared femtosecond laser pulses

Photoinduced processes of Sm3+-doped sodium borate glasses under high-power, 800 nm femtosecond laser irradiation have been studied. Both the photoreduction of Sm3+ to Sm2+ and the formation of intrinsic defects are observed at an irradiance well below the threshold for laser-induced damage. We propose that these photoinduced processes arise from the linear and two-photon absorption of the short-wavelength component of the supercontinuum and the subsequent ionization of the glass matrix. Photochemical hole burning (PHB) has been observed for 5D0–7F0 transition of Sm2+ in the sodium borate glasses irradiated with near-infrared femtosecond laser pulses. The efficiency of hole burning at 77 K was about 5 times higher in the irradiated glasses than in thermally reduced glasses. We consider that both the metastable Sm2+ and the intrinsic defects were responsible for the highly efficient PHB phenomenon.