Photoinduced valence changes of samarium ions inside a silica-based glass with near-infrared femtosecond-laser pulses: Materials for three-dimensional optical memory

We report photoinduced valence changes of samarium ions inside a silica-based glass using focused femtosecond-laser pulses of 800 nm wavelength. Photoluminescence spectra reveal that femtosecond-laser irradiation reduces Sm3+ in the vicinity of the focal point of the laser beam to Sm2+, The mechanism of the photoinduced reduction of Sm3+ is discussed based on optical absorption and electron spin resonance spectra.