Fig. 1. Optical absorption of (a) as-fabricated and (b) high-temperature (1350°C for 10 h) annealed YAG transparent ceramics after UV irradiation (inset: variation with the irradiation time).

Fig. 2. Gaussian fitting of optical absorption of colored YAG ceramics using least-squares method.

Fig. 3. Optical transmittance of UV-irradiated YAG ceramics after annealing at various temperatures.

Fig. 4. Contour plots of TL in (a) as-sintered and (b) annealed YAG transparent ceramics from −190°C to 400°C with the heating rate of 60°C/min. (c) Comparison of TL glow curves of as-sintered and annealed YAG transparent ceramics. (d) TL emission spectra for as-sintered YAG ceramics (at −20°C and 120°C) and annealed YAG transparent ceramics (at −25°C). Plots of ln I versus 1/T for TL peak (∼20°C/25°C) for (e) as-sintered and (f) annealed YAG transparent ceramics with rate of 60°C/min.

Fig. 5. PALS results for as-sintered YAG ceramics at 1840°C for 8 h together with deconvolution analysis of lifetime data. (Top) Semi-log plot lifetime distribution up to 8 ns; (bottom) residual difference between the experimental and best-fit results.

Fig. 6. (a) Thermally etched surface and (b) fracture surface of YAG transparent ceramics. (c) HR-TEM image of grain boundary with corresponding SAED pattern as inset of YAG transparent ceramics.

Fig. 7. Lifetime results of τ2 and I2 in YAG transparent ceramics: (a) solarization effect; (b) low-temperature annealing treatment of UV-irradiated ceramics.