[en] We report on MgAl_2O_4 planar waveguides produced using different energies and fluences of C-ion implantation at room temperature. Based on the prism coupling method and end-face coupling measurements, light could propagate in the C-ion-implanted samples. The Raman spectra results indicate that the MgAl_2O_4 crystal lattice was damaged during the multi-energy C implantation process, whereas the absorption spectra were hardly affected by the C-ion implantation in the visible and infrared bands.

[en] We report the fabrication of a planar optical waveguide in a Ca_0_._4Ba_0_._6Nb_2O_6 crystal by irradiation with 6.0 MeV oxygen ions. We measured the guiding mode by the prism-coupling method at 633 nm and 1539 nm. The near-field intensity distributions were measured by the end-face coupling setup at a wavelength of 633 nm. The reflectivity calculation method (RCM) was used for reconstructing refractive index profiles. SRIM was used to simulate the electronic and nuclear stopping power caused by oxygen ion irradiation, and the finite-difference beam propagation method (FD-BPM) was used to simulate the near-field intensity distributions. Micro-Raman spectra were measured at room temperature in air to study the differences between the substrate and waveguide region

[en] We reported a planar waveguide structure on an Nd"3"+:Li_6Y(BO_3)_3 sample fabricated using 6 MeV C ion irradiation at a fluence of 2.5 × 10"1"5 ions/cm"2. Guided modes were detected in the visible and near-infrared wavelength regions. The refractive index profiles were reconstructed based on the effective refractive index functions. The near-field light intensity files in the visible and near-infrared bands were measured using the end-face coupling method with different light sources.

[en] We present the effects of self-gravity on the vertical structure and neutrino luminosity of the neutrino-dominated accretion disks in cylindrical coordinates. It is found that significant changes of the structure appear in the outer region of the disk, especially for high accretion rates (e.g., ≳ 1 M_☉ s^–1), and thus cause the slight increase in the neutrino luminosity. Furthermore, the gravitational instability of the disk is reviewed by the vertical distribution of the Toomre parameter, which may account for the late-time flares in gamma-ray bursts and the extended emission in short-duration gamma-ray bursts.

[en] We investigate the thermal stability of optically thin, two-temperature, radiative cooling-dominated accretion disks. Our linear analysis shows that the disk is thermally unstable without magnetic fields, which agrees with previous stability analysis on the Shapiro-Lightman-Eardley disk. By taking into account the effects of magnetic fields, however, we find that the disk can be, or partly be, thermally stable. Our results may be helpful to understand the outflows in optically thin flows. Moreover, such radiative cooling-dominated disks may provide a new explanation of the different behaviors between black hole and neutron star X-ray binaries on the radio/X-ray correlation

[en] Lithium sulfur battery has been identified as a promising candidate for next storage devices attributing to ultrahigh energy density. However, non-conductive nature of sulfur and shuttling effect of soluble lithium polysulfides are intractable remaining problems. Herein, we develop a highly conductive nickel-rich Ni₁₂P₅/CNTs hybrid with high specific surface area as sulfur host to address these issues. The polar nature of Ni₁₂P₅/CNTs can significantly relieve the shuttle effect by means of a strong affinity towards lithium polysulfides and enhance kinetics of polysulfides redox reactions. In addition, the Ni₁₂P₅/CNTs with a superior conductivity (500 S·m⁻¹) and high surface area of 395 m²·g⁻¹ enables the effective electron transfer and expedited interfacial reaction. As a result, Ni₁₂P₅/CNTs hosted sulfur cathode exhibits high rate capability (784 mAh·g⁻¹ at 4 C) and stable cycling performance with a negligible capacity fading of 0.057 % per cycle over 1,000 cycles at 0.5 C. This work paves an alternative way for designing high performance sulfur cathodes involved metal-rich phosphides. .

[en] The tetragonal γ-LiAlO₂ crystal, known as a promising solid breeding material in future fusion reactors, has attracted much attention for its irradiation effects. This work focused on the Raman effects in ion-implanted γ-LiAlO₂. Ga ions of 30, 80 and 150 keV were implanted on the z-cut γ-LiAlO₂ sample surfaces at a fluence of 1 × 10¹⁴ ions/cm² or 1 × 10¹⁵ ions/cm². The average ion range varied from 230 to 910 Å. The Raman spectra were collected from the implanted surfaces before and after the implantation. Evident changes were reflected in the Raman modes intensities, with abnormal increments for the most detected modes. According to the assignments of Raman modes, the Al-O vibration was enhanced to a greater extent than the Li-Al-O vibration, and the LiO₄-AlO₄ vibration gained a lesser enhancement. The discussion, including the factors of roughness, crystalline disorder and influence by Ga ions, attempts to explain the increments of Raman intensity.

[en] To explore the evolution of γ-LiAlO₂ under ion irradiation at low energy, we implanted Ga ions of 30, 80 and 150 keV at fluences of 1 × 10¹⁴ and 1 × 10¹⁵ ions/cm² in z-cut γ-LiAlO₂ samples, respectively. The implantation resulted in damage regions dominated by nuclear energy losses at depth of 232 Å, 514 Å, and 911 Å beneath the surface, respectively, which was simulated by the Stopping and Range of Ions in Matter program. The irradiated γ-LiAlO₂ were characterized with atomic force microscope, Raman spectroscopy, X-ray diffraction and Rutherford backscattering in a channeling mode for morphology evolution, structure information and damage profiles. The interesting and partly abnormal results showed the various behaviors in modification of surface by Ga ions implantation.

[en] We report the formation of two waveguide layers in a lithium niobate crystal by irradiation with swift heavy Kr ions with high (GeV) energies and ultralow fluences. The micro-Raman spectra are measured at different depths in the irradiated layer and show that the high electronic energy loss can cause lattice damage along the ion trajectory, while the nuclear energy loss causes damage at the end of the ion track. Two waveguide layers are formed by confinement with two barriers associated with decreases in the refractive index that are caused by electronic and nuclear energy losses, respectively. (rapid communication)

[en] Ion irradiation has been a popular method to modify properties of different kinds of materials. Ion-irradiated crystals have been studied for years, but the effects on microstructure and optical properties during irradiation process are still controversial. In this paper, we used 6 MeV C ions with a fluence of 1 × 10¹⁵ ion/cm² irradiated Y₂SiO₅ (YSO) crystal at room temperature, and discussed the influence of C ion irradiation on the microstructure, mechanical and optical properties of YSO crystal by Rutherford backscattering/channeling analyzes (RBS/C), X-ray diffraction patterns (XRD), Raman, nano-indentation test, transmission and absorption spectroscopy, the prism coupling and the end-facet coupling experiments. We also used the secondary ion mass spectrometry (SIMS) to analyze the elements distribution along sputtering depth. 6 MeV C ions with a fluence of 1 × 10¹⁵ ion/cm² irradiated caused the deformation of YSO structure and also influenced the spectral properties and lattice vibrations.