采用双折射晶体实现大功率半导体列阵激光器偏振复合

根据大功率半导体列阵激光器输出光束的偏振特性,基于偏振复用的原理,利用双折射晶体YVO4进行两只大功率半导体列阵激光器的偏振合束研究。利用按照理论计算值生长的双折射晶体和特殊设计的光路系统实现功率复用效率66%,经过耦合镜聚焦后得到光斑大小为1.25 mm×0.12 mm,功率密度为2.74×104W/cm2。

Comparison of Loss and Crosstalk Characteristics of SOI Based Intersecting Waveguides with Different Bend Structures

By means of two dimension beam propagation method (2D-BPM) with high order Pade approximation, behaviors of SOI waveguide based bend intersections with variant bending radius are simulated and analized. The result shows that crosstalk of intersections decreases with the increase of bending radius and intersecting angle. Furthermore, loss and crosstalk characteristics of bend intersections formed by sine bend, cosine bend and arc bend are compared. Sine bend based structures are proved that it can present lowest loss and smallest crosstalk properties among the three and may find their wide application in the design of bend intersections and other more complicated photonic devices and circuits.

Fabrication of SiGe/Si Multi-Quantum Wells Resonant-Cavity-Enhanced Detector

A SiGe/Si multi-quantum wells resonant-cavity-enhanced(RCE) detector with high reflectivity bottom mirror is fabricated by a new method.The bottom mirror is deposited in the hole,which is etched from the backside of the sample by ethylenediamine-pyrocatechol-water(EPW) solution with the buried SiO2 layer in SOI substrate as the etching-stop layer.Reflectivity spectrum indicates that the mirror deposited in the hole has a reflectivity as high as 99% in the range of 1.2～1.5μm.The peak responsivity of the RCE detector at 1.344μm is 1.2mA/W and the full width at half maximum is 12nm.Compared with the conventional p-i-n photodetector,the responsivity of RCE detector is enhanced 8 times.

我国重质量丰中子新核素的合成、鉴别和研究实现重要突破

本文叙述了远离β稳定线新核素尤其是重质量丰中子新核素合成和研究的重要意义,介绍了合成和鉴别的技术路线,报告了我国在该领域的研究现状。

L-shell x-ray yields and production cross sections of Zr and Mo bombarded by slow highly charged Ar16+ ions

The L-shell x-ray yields of Zr and Mo bombarded by slow Ar16+ ions are measured. The energy of the Ar16+ ions ranges from about 150keV to 350keV. The L-shell x-ray production cross sections of Zr and Mo are extracted from these yields data. The explanation of these experimental results is in the framework of the adiabatic directionization and the binding energy modified BEA approximation. We consider, in the slow asymmetric collisions such as Ar and Mo/Zr, the transient united atoms (UA) are formed during the ion-surface interaction and the direct-ionization is the main mechanism for the inner-shell vacancy production. Generally, the theoretical results are in good agreement with the experimental data.

THE ISOSPIN DEPENDENCE OF THE NUCLEAR PHASE TRANSITION NEAR THE CRITICAL POINT

The experimental results reveal the isospin dependence of the nuclear phase transition in terms of the Landau Free Energy description of critical phenomena. Near the critical point, different ratios of the neutron to proton concentrations lead to different critical points for the phase transition which is analogous to the phase transitions in He-4-He-3 liquid mixtures. The antisymmetrized molecular dynamics (AMD) and GEMINI models calculations were also performed and the results will be discussed as well.