Synthesis of LaF3 nanocrystals by laser-induced Nd3+ atom heat processing in oxyfluoride glasses

Oxyfluoride glasses with the compositions of 33SiO2–21Al2O3–33NaF–9LaF3–4Nd2O3–xErF3 (mol%), x = 0 and 0.5, are prepared using a conventional melt-quenching technique, and the laser-induced crystallization method using continuous-wave (cw) diode lasers with a wavelength of λ = 795 nm is applied to form LaF3 crystals on the glass surface. It is found from X-ray diffraction analyses and micro-photoluminescence spectra that Nd3+-, Er3+-doped LaF3 crystals with a diameter of ∼23 nm are patterned by laser irradiations with a laser power of 1.8 W and a laser scanning speed of 10 μm/s. It is proposed that the lines patterned by laser irradiations are consisted of the composite of Nd3+-doped LaF3 nanocrystals and the SiO2-based oxide glassy phase. It is suggested that the combination of cw diode laser (λ = 795 nm) irradiations and the non-radiated relaxation process in the f–f transition level of 4F5/2 → 4I9/2 of Nd3+ ions is effective in the spatially selected local patterning of fluoride crystals in oxyfluoride glasses with Nd3+ ions.