| The upconversion luminescence characteristics of Er3+-doped YVO4 crystal were studied in the thesis. The experimental and theoretic results are helpful to the application of laser devices and upconversion devices. The main contents are listed as follows:1. The absorption, luminescence and upconversion spectra of Er3+:YVO4 crystal were investigated at room temperature. The characteristics of optical radiation of this material were investigated by J-0 theory. The absorption, luminescence and upconversion spectra by different pumping direction were analyzed, and the optimum pumping direction for upconversion luminescence was obtained.2. The upconversion spectrum of Er3+:YVO4 under 980 nm excitation was measured. The evolutions of state populations of Er3+ ions system under the pump of 980nm laser were analyzed. Base on the rate equation theory, a dynamic model of frequency upconversion in Er3+:YVO4 was proposed. The upconversion coefficients (C22 and C33) were evaluated by solving the rate equations and fitting the experimental decay curves. Finally, the 550nm emission decay curve under the exciting of 980nm laser was measured, and the upconversion luminescence mechanism was analyzed.3. The photoluminescence characteristics of 1550nm emission pumping at different wavelengths in Er3+:YVO4 were investigated by using the Dexter theory and rate equation theory. The cross relaxation rates (P1, P2) were obtained by the Dexter theory. The transition model of Er3+ ions pumping at different wavelengths was proposed. The photoluminescence characteristics under different pumping intensity and different Er3+-doped concentration were compared. Moreover, the effect of ETU and ESA to 1550nm emission was analyzed. The effect of cross relaxation to 1550nm emission was analyzed. |
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