Yiguang Jiang

Er3+-doped transparent glass ceramics containing micron-sized SrF2 crystals for 2.7 μm emissions

Er3+-doped transparent glass ceramics containing micron-sized SrF2 crystals were obtained by direct liquid-phase sintering of a mixture of SrF2 powders and precursor glass powders at 820 °C for 15 min. The appearance and microstructural evolution of the SrF2 crystals in the resulting glass ceramics were investigated using X-ray diffraction, field-emission scanning electron microscopy and transmission microscopy. The SrF2 crystals are ~15 μm in size and are uniformly distributed throughout the fluorophosphate glass matrix. The glass ceramics achieve an average transmittance of 75% in the visible region and more than 85% in the near-IR region. The high transmittance of the glass ceramics results from matching the refractive index of the SrF2 with that of the precursor glass. Energy dispersive spectroscopy, photoluminescence spectra, and photoluminescence lifetimes verified the incorporation of Er3+ into the micron-sized SrF2 crystals. Intense 2.7 μm emissions due to the 4I11/2 → 4I13/2 transition were observed upon excitation at 980 nm using a laser diode. The maximum value of the emission cross section of Er3+ around 2.7 μm is more than 1.2 × 10−20 cm2, which indicates the potential of using transparent glass ceramics containing micron-sized SrF2 crystals for efficient 2.7 μm lasers and amplifiers.

Europium doped transparent glass ceramics containing CaF2 micron-sized crystals: structural and optical characterization

Transparent glass ceramics containing CaF2 micron-sized crystals were prepared using a modified liquid-phase sintering route. The morphology and microstructural evolution of the CaF2 crystals before and after liquid-phase sintering were examined using X-ray diffraction, field-emission scanning electron microscopy and transmission microscopy. After sintering at 800 °C for 10 min, the CaF2 crystals were approximately 20 μm in size and were uniformly distributed throughout a precursor glass prepared using melt-quenching method. The glass ceramic containing CaF2 micron-sized crystals prepared using liquid-phase sintering achieved the highest in-line transmittance of 76% in the visible region and 92% in the near-IR region. High near-IR transmittance of glass ceramics was attributed to the matching of the refractive index of the precursor glass with that of CaF2 in the near-IR region. The luminescence properties and local environment of Eu3+ in the precursor glass and glass ceramic were investigated using photoluminescence spectra, photoluminescence lifetimes and phonon sideband spectroscopy, and the results determined that some of the Eu3+ ions in the precursor glass incorporate into CaF2 micron-sized crystals after sintering and enter C4v site symmetry.

Influence of dopant concentration on the transparent and thermal properties of Nd 2 O 3 -doped alumina translucent ceramics

Abstract The transparent and thermal developments of high-purity Al 2 O 3 doped with different levels of Nd 2 O 3 were investigated. Dopant levels ranged from 500–1500 ppm (Nd/Al atomic ratio). The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, transmittance spectroscopy and specific heat measurement. Results revealed that with proper Nd doped, Nd 3+ ions solid dissolved in Al 2 O 3 lattice, resulting in small and uniform grain and high bonding vibration, which was beneficial to transparent and thermal properties. With 1000 ppm Nd doped, Al 2 O 3 translucent ceramics showed a total transmittance of 89% and thermal conductivity of 41.7 W/m/K, indicating a potential application as substrate for effective heat dissipation and multi emitting surface in LEDs module.

Re-clustering of neodymium ions in neodymium, buffer ion-codoped alkaline-earth fluoride transparent ceramics

We systematically present the relationship between the optical properties and deformation of Nd,B-codoped MF2 (B = buffer ions; M = alkaline earth metal ions) transparent ceramics. Re-clustering of Nd3+ ions in ceramics was experimentally observed for the first time. The mechanism of re-clustering was studied.