Crystallization of 21.25Gd2O3 –63.75MoO3–15B2O3 glass induced by femtosecond laser at the repetition rate of 250kHz

We report the formation of β′-Gd2(MoO4)3 (GMO) crystal on the surface of the 21.25Gd2O3–63.75MoO3–15B2O3 glass, induced by 250kHz, 800nm femtosecond laser irradiation. The morphology of the modified region in the glass was clearly examined by scanning electron microscopy (SEM). By micro-Raman spectra, the laser-induced crystals were confirmed to be GMO phases and it is found that these crystals have a strong dependence on the number and power of the femtosecond laser pulses. When the irradiation laser power was 900mW, not only the Raman peaks of GMO crystals but also some new peaks at 214cm−1, 240cm−1, 466cm−1, 664cm−1 and 994cm−1which belong to the MoO3 crystals were observed. The possible mechanisms are proposed to explain these phenomena.