摘要CaWO4 polycrystals with fixed Yb3+ and various Er3+ concentrations are synthesized via the high temperature solid state method. The crystal structure of the polycrystals is characterized by means of x−ray diffraction. The upconversion properties of the polycrystals under the 980 nm excitation are investigated. Intense emission bands centered at 530 nm and 552 nm correspond to the transitions 2H11/2→4I15/2 and 4S3/>2→4I15/2 of Er3+, respectively. The dependence of intensity of the green emission on the pump power and possible upconversion mechanism are discussed. Quantitative analysis of dependence of upconversion emission intensity on the pump power of a laser diode indicates that two-photon processes are responsible for both 530 nm and 552 nm green upconversion emissions.
Abstract：CaWO4 polycrystals with fixed Yb3+ and various Er3+ concentrations are synthesized via the high temperature solid state method. The crystal structure of the polycrystals is characterized by means of x−ray diffraction. The upconversion properties of the polycrystals under the 980 nm excitation are investigated. Intense emission bands centered at 530 nm and 552 nm correspond to the transitions 2H11/2→4I15/2 and 4S3/>2→4I15/2 of Er3+, respectively. The dependence of intensity of the green emission on the pump power and possible upconversion mechanism are discussed. Quantitative analysis of dependence of upconversion emission intensity on the pump power of a laser diode indicates that two-photon processes are responsible for both 530 nm and 552 nm green upconversion emissions.
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2011, Vol. 28 
