Characteristics of Upconversion Luminescence of CaF2:Er Powders Excited by 1.5-µm Laser Radiation

The characteristics of upconversion luminescence of CaF2:Er crystalline powders upon laser excitation of Er3+ ions to the 4I13/2 level at a wavelength of 1531.8 nm are studied. The upconversion luminescence energy yields for the spectral regions of 380–780 and 380–1100 nm are determined. It is found that upconversion luminescence of CaF2:Er powders with Er3+ concentrations of 0.5, 2, 4, 6, 8, 10, 11, 13, 15, and 17% is characterized by correlated color temperatures of 5100, 2142, 1726, 1738, 1773, 1757, 1762, 1765, 1735, and 1714 K, respectively.