PbF2: Er[Formula: see text], Yb[Formula: see text] phosphors with the property of dual-mode conversion were prepared successfully by the high-temperature solid-state reaction method. The structure and luminescence properties of the samples were characterized by X-ray diffraction (XRD) and fluorescence spectrum method. The luminescence mechanisms of the samples under single ultraviolet (UV) or infrared (IR) light source excitation and UV[Formula: see text]IR co-excitation were analyzed. Under 376, 980 and 1550[Formula: see text]nm excitation, the phosphors showed intense green and red emission, the green emission (520–570[Formula: see text]nm) and the red emission (650–680[Formula: see text]nm) originated from the 2H[Formula: see text]I[Formula: see text], 4S[Formula: see text]I[Formula: see text] and 4F[Formula: see text]I[Formula: see text] transitions of Er[Formula: see text] ions, respectively. The fluorescence enhancement effect was observed in the UV and IR co-excited samples, which is derived from the infrared photon reabsorption of the ions at metastable energy levels.
Ultra-compact reconfigurable device for mode conversion and dual-mode DPSK demodulation via inverse design
