Fig. 1

Transparent YAG-Al₂O₃ composite nanoceramics. a Bright field TEM micrograph showing the nanometer-scale microstructure of the fully crystallized material (scale bar corresponds to 100 nm). The selected area electron diffraction pattern shows the crystallinity of the sample with both YAG and Al₂O₃ reflections. The size distribution with standard deviation (σ) of the YAG crystals is also embedded. b X-ray diffraction of the YAG-Al₂O₃ ceramic crystallized from a 26 Y₂O₃–74 Al₂O₃ glass via a simple 2 h heat treatment at 1100 ℃ in air. The Rietveld refinement leads to a 79±2 wt% content of YAG (21±2 wt% of γ-Al₂O₃). c HRTEM micrograph of the YAG-Al₂O₃ ceramic showing the presence of two crystalline phases: thin Al₂O₃ areas surrounding YAG nanograins sharing grain boundaries (scale bar corresponds to 20 nm). The related FFT patterns are embedded. d Transmission spectra in UV–VIS–NIR and MIR region of the YAG-Al₂O₃ ceramic measured through a 1.5 mm thick sample. The dashed gray line corresponds to the theoretical maximum transmission of YAG[53] (the refractive index of YAG single crystal and YAG-Al₂O₃ ceramic at 589 nm is 1.82 and 1.77, respectively). The photograph of the YAG-Al₂O₃ ceramic sample (diameter = 4.5 mm) placed 2 cm above the text is embedded