•LuYAG:Pr ceramic scintillators were prepared successfully without any additives.•With 0.15% Pr3+ doping, the prepared LuYAG:Pr ceramics displays a light output of 28500 ph/MeV at 3 μs shaping time.•The light yield of the obtained LuYAG:Pr ceramics is higher than that of the LuAG:Pr ceramic scintillators ever report.•The vacuum ultraviolet and electron spin resonance experiment were performed to explain the reason for this improvement.Y3+ admixing Lu3Al5O12:Pr ceramics are fabricated successfully by the solid state reaction method and further optimized by an air-annealing process. Optical absorption, photoluminescence spectra and scintillation properties such as radioluminescence, and light output are measured and compared with those of the Y3+ free LuAG:Pr ceramics. Positive effect of Y3+ codopant consists mainly in the significant increase of scintillation light output, as well as the decrease of relative intensity of slow component. With 0.15% Pr3+ codoping, the obtained LuYAG:Pr ceramic displays a light output of 28500 ph/MeV at 3 μs shaping time, higher than that of the LuAG:Pr ceramic scintillators ever report. The effect of Y3+ admixture is further explained by vacuum ultraviolet and electron spin resonance experiment.

Ultra-fine, well dispersed Yb: (LuxSc1−x)2O3 nanopowders were synthesized by a carbonate co-precipitation method, in which ammonium hydrogen carbonate (NH4HCO3) and ammonium hydroxide (NH4OH) were mixed at the molar ratio of 3:1 as the precipitant and ammonia sulfate ((NH4)2SO4) as dispersing agent. The precursor calcined at different temperatures was investigated by TG/DTA, FT-IR and XRD to choose the best calcination temperature. Transparent Yb: (LuxSc1−x)2O3 ceramics with in-line transmittance of 46.2% at 1200 nm wavelength were sintered from the nanopowders calcined at 1100 °C for 4 h. The emission spectrum of Yb: (LuxSc1−x)2O3 was found inhomogeneously broadened compared to Yb: Sc2O3. Broad emission band are very beneficial in generating ultra-fast pulse. Results indicate that Yb: (LuxSc1−x)2O3 is a kind of promising ultra-fast laser material.

Scattering defects, which severely affect the optical quality of materials, have been investigated in polycrystalline ZnSe and ZnS grown by chemical vapor deposition (CVD). Cr ions were introduced into the grown hosts (Cr2+:ZnS/ZnSe) as mid-infrared laser gain media by the post-growth diffusion method. Decrease of the as-grown defects was observed after the diffusion process giving rise to an improvement in optical quality of doped materials. Meantime, the advantages of post treatment (HIP) on CVD hosts became less obvious after the doping process. The reparative effect on internal defects, as we firstly described here, is attributed to the secondary crystallization of host crystals caused by the long period, high temperature diffusion process. Evidences could be found in the microstructure evolutions including the growth of grains, densified grain boundaries and intracrystalline inclusion clusters.

Multilayered carbon nanotubes/silicon dioxide (CNTs/SiO2) electromagnetic wave absorbing ceramic matrix composite material was fabricated by hot-pressed sintering. The gradient layer structure was designed to improve its absorbing properties. The multilayered CNTs/SiO2 composite was shaped by adding five kinds of mixed powders with different CNTs contents (0 wt%, 2.5 wt%, 5 wt%, 7.5 wt% and 10 wt%) to the graphite die in turn, and its average CNTs content was 5 wt%. Meanwhile, a single layered composite with the same content of CNTs (5 wt%) was fabricated as a contrast sample. The electromagnetic interference (EMI) shielding effectiveness (SE) and reflecting effectiveness (RE) were studied with insertion loss (IL) and return loss (RL) measurements in the range of 8–12 GHz. The results showed that the gradient multilayered sample had a better absorbing effectiveness and its absorbance was 1.5 times as high as the single layered sample’s, while their SEs were almost the same.Research highlights► Gradient multilayered CNTs/SiO2 electromagnetic wave absorbing composite was fabricated. ► Gradient multilayer structure was designed to improve the absorbing properties. ► The absorbance of the multilayered sample was 1.5 times as high as the single layered sample’s. ► The shielding effectivenesses of the two samples were almost the same.

Transparent Fe2+:ZnS polycrystals are 3–5 μm mid-IR laser gain materials with great importance. In this paper, a novel route combining wet-chemical co-precipitation, hot-pressed sintering and post hot isostatic pressing (HIP) treatment was proposed for Fe2+:ZnS transparent ceramics. Fe2+:ZnS powders were synthesized successfully by the wet-chemical co-precipitation method, which was suitable for particle size and morphology controlling and then ceramics consolidation. Transparent Fe2+:ZnS ceramics with comparatively high optical quality were successfully fabricated by two step sintering method combining hot pressing and post-HIP treatment. This approach is a promising candidate for fabricating Fe2+:ZnS ceramics with large size, low cost, short cycle, and flexible concentration distribution design.

•Li+ co-doped LuAG: Ce, Li ceramics with various Li concentrations fabricated.•Positive effects of Li+ on the Ce3+/4+ state and scintillation properties revealed.•LuAl antisite defects in LuAG:Ce ceramics depressed by Li codoping.•The highest light yield value ever reported in LuAG:Ce based scintillators.Monovalent Li+ codoped Lu3Al5O12:Ce (LuAG:Ce) optical ceramics were fabricated by solid state reaction method and further optimized by an air-annealing process. Optical absorption, radioluminescence spectra and scintillation properties such as light yield, scintillation decay times and afterglow were measured and compared with those of the Li+ free LuAG:Ce ceramic and the commercial LuAG:Ce single crystal samples. Positive effect of Li+ codopant consists mainly in the significant increase of scintillation light yield, acceleration of scintillation decay as well as the decrease of afterglow intensity. With 0.3% Li codoping, the obtained LuAG:Ce,Li ceramic displays a light yield of ∼29200 ph/MeV at 10 μs shaping time, higher than that of the LuAG:Ce single crystal and optical ceramic scintillators ever reported. The partial conversion of the stable Ce3+ to Ce4+ centers and the shallow and deep traps effect suppression by the Li+ codoping are discussed.