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We report on the effect of 500 keV He + ion implantation with a fluence of 3 × 1 0 1 6  ions/cm2 on Rb + -K + ion exchanged KTiOPO4 optical waveguide. The refractive index distribution after ion implantation, ion exchange, and ion implantation and subsequent ion exchange were reconstructed by reflectivity calculation method, inverse Wentzel–Kramers–Brillouin, and intensity calculation method, respectively. The near field intensity distribution of the waveguides was simulated by Beam Propagation Method. The phase analysis of the samples was measured by X-ray diffraction technique. The damage layer formed in the depth of maximum nuclear energy deposition by ion implantation acts as a barrier to block the ions diffusion into the sample. Results exhibit that ion implantation and subsequent ion exchange are effective means for optical waveguide formation. [ABSTRACT FROM AUTHOR]

The process of conversion from -Ga2O3 single crystal to gallium nitride (GaN) in an atmosphere of NH3 by chemical vapor deposition is investigated. The surface morphology and microstructure of the GaN nanoparticles are observed by scanning electron microscope, which indicates that the growth of GaN is via the Volmer-Weber mechanism. The -Ga2O3 is firstly evaporated at high temperature to form the porous layer, followed by the surface-defect induced GaN nucleation formation. The crystalline structure and epitaxial relationship of the GaN nanoparticles are investigated by X-ray diffraction (XRD) via -, showing GaN (0002) and (0004) diffraction peaks in the XRD spectra. It is concluded that the polycrystalline GaN film with hexagonal structure has a strong c-axis preferential orientation. [ABSTRACT FROM AUTHOR]

Abstract: The KTiOAsO4 crystals have been implanted with 500keV Er ions at a fluence of 3.0×1015 ions/cm2 with the aim of optically doping the material in the near surface region. By combing the Stopping and Range of Ions in Matter results and X-ray diffraction results, we may conclude that the surface of the KTiOAsO4 crystal suffered serious damage after Er+ ion implantation. The depth distribution and annealing diffusion behavior of Er atoms were determined using the Rutherford backscattering technique. Photoluminescence emission at room temperature with a wavelength of 1540nm was observed in the annealed sample. [Copyright &y& Elsevier]

Abstract: Potassium titanyl arsenate (KTiOAsO4 or KTA) crystal was ion implanted by 500keV Tm+ ions with a fluence of 5.5×1014 ions/cm2 at room temperature. The depth profile of implanted Tm+ ions into KTiOAsO4 crystal was measured by Rutherford backscattering spectrometry and calculated by the stopping and ranges of ions in matter (SRIM'2006) computer code. The results of SRIM'2006 calculation and X-ray diffraction analysis show that the surface of KTA crystal was almost amorphous state due to the Tm+ ion implantation. The excitation and emission spectrum of Tm implanted KTA at room temperature were measured. The visible emission spectrum consists of a main contribution in the blue region at 467nm corresponding to the Tm transition from the 1D2 to the 3F4 ground state. [Copyright &y& Elsevier]

Abstract: We report on optical channel waveguide in RbTiOPO4 crystal produced by photographic masking and following direct C3+ ion implantation at 6.0MeV with a fluence of 5×1013 ions/cm2. The absorption spectra show that there are fewer point defects in the waveguide region, forming “crystal waveguide”. The bright near field intensity distribution of the transverse-electric mode indicate that the light can be guided in a well confined way almost without leakage. Considering the Fresnel reflection at the air–crystal interface is about 15%, we obtained a loss of 1.7dB/cm for the channel waveguide at wavelength of 633nm. [Copyright &y& Elsevier]

During the progressive exploration of the Jingbian Gas Field in the Ordos Basin, multiple gas-bearing regions have been discovered in the dolomite reservoirs in the Middle Ordovician assemblages of Ordovician in the Jingxi area, but these gas-bearing regions are significantly different in terms of gas enrichment degrees, especially in the midland of Jingxi area. However, the reasons for it have not been figured out. On the basis of drilling data, logging data, reservoir data and other geological data, we compared the characteristics of natural gas accumulation of three areas in the midland of Jingxi area and analyzed the main factors controlling the gas accumulation.It is shown that the natural gas accumulation of the study area is mainly controlled by the following factors. Firstly, gas charging capacity of hydrocarbon-supplying windows controls natural gas enrichment degree. Secondly, the connectivity of transporting pathway affects the position of natural gas accumulation. And thirdly, the pore ratio and permeability of reservoir control the scale of natural gas accumulation. It is concluded that Ma55 and Ma65 sub-members are favorable exploration areas in the north of Su127 area, Su203 area and the south of Tao15 area, and the exploration potential of Ma75-Ma105 sub-member is relatively poor. [ABSTRACT FROM AUTHOR]

Abstract: The planar waveguide in x-cut Yb:GdVO4 crystal has been fabricated by 6.0MeV carbon ion implantation with the fluence of 1×1014 ions/cm2 at room temperature. The modes of the waveguide were measured by the prism-coupling method with the wavelength of 633nm and 1539nm, respectively. An enhanced ordinary refractive index region was formed with a width of about 4.0μm beneath the sample surface to act as a waveguide structure. By performing a modal analysis on the observed transverse magnetic polarized modes, it was found that all the transverse magnetic polarized modes can be well-confined inside the waveguide. Strong Yb-related photoluminescence in Yb:GdVO4 waveguide has been observed at room temperature, which reveals that it exhibits possible applications for integrated active photonic devices. [ABSTRACT FROM AUTHOR]