UPCONVERSION FLUORESCENCE IN ZnWO4:Er3+CRYSTAL BY LD EXCITED

? Single crystals of ZnWO4 ∶ Er3+(Er:0.02 mol) have been grown by the Czochralski method and their absorption and excitation spectra are measured. It is observed that the upconversion luminescence phenomenon in the crystals by laser diode(LD)excited with 500 mW power at 966 nm wavelength. The most strong fluorescence intensity are occurred at 547 and 558 nm wavelength. Studies on emission spectra shown that the excitation process of upconversion luminescence relatives to the stepwise twophoton absorption.