Upconversion of Nd3+ in Nd3+-Yb3+ Co-Doped Transparent Glass Ceramics Embededing Nano Ca5(Po4)3F Crystals

A transparent glass ceramics co-doped with Nd³⁺-Yb³⁺ was fabricated by the high-temperature melting technique. X-ray diffraction and transmission electron microscope results demonstrated that Ca₅(PO₄)₃F (FAP) nanocrystals with a mean size of 30 nm were homogeneously precipitated among the glass matrix. Upconversion (UC) luminescence of Nd³⁺ sensitized by Yb³⁺ was investigated, and emission bands centered at 751, 806 and 875 nm, which corresponds to the ⁴F_7/2→⁴I_9/2, ⁴F_5/2→⁴I_9/2 and ⁴F_3/2→⁴I_9/2 transitions of Nd³⁺, respectively, could be observed. The results show that the order parameter n of UC luminescence intensities depended on excitation pump power increase remarkably after precipitation of nano FAP, which indicating energy distance E = E_UC - E(⁴F_3/2) increase and Nd³⁺ may incorporate into the precipitated nanocrystals.