Figure 3

(a) Visual demonstration of the OSL in ZrO2 sample, which was excited by UV-irradiation in advance. The bright region (encircled by dashed line) corresponds to the irradiation spot. (b) Intensity of the afterglow PL and subsequent OSL as a function of time. (c) The spectra of afterglow PL and OSL (stimulated by NIR-laser with λsti = 808 nm).