日本岛津产ICP1000型等离子体发射光谱仪的改造方法(硬件部分)

本文提出了对日本岛津产 ICP10 0 0型等离子体发射光谱仪的改造方法 ,并详细介绍了具体仪器的硬件改造过程 ,以及改造后的考核测试结果 ,为国内该种大型精密光学仪器的改造做了有益的尝试。     

脉冲激光烧蚀碲镉汞材料的等离子体发射谱

脉冲激光辐照处于不同背景气压下的Hg0.8Cd0.2Te材料表面,用时间和空间分辨诊断技术探测了激光照射后产生的等离子体发射谱,根据所获得的飞行时间谱测量了等离子体中粒子的出射速度,结果表明粒子速度随着出射距离的增加迅速减小,且背景气压对出射速度有很大的影响,而激光能量对粒子速度的影响不大。另外根据谱线的展宽计算了等离子体中的电子密度,结果表明,电子密度在激光辐照样品后的短时间内迅速减小,且电子密度最大的位置不是出现在靶的表面而是在距表面一定距离处。     

中能重离子碰撞中的中子(质子)发射的同位旋效应

利用同位旋相关的量子分子动力学,对中能重离子碰撞过程中的中子和质子发射的同位旋效应进行了分析.计算结果表明在有动量相关作用条件下,在很宽的能量和碰撞参数范围内,缺中子碰撞系统的中子(质子)发射数强烈地依赖于同位旋相关的核子–核子碰撞截面,而较弱地依赖于对称势.在对丰中子碰撞系统的研究中,上述规律减弱.这样就可以通过实验上对缺中子碰撞系统的中子(质子)发射数的探测,来提取介质中同位旋相关核子–核子碰撞截面的知识.     

测发控系统方舱结构研究

把航天装备送入空间的快速发射,对测发控系统提出了便捷、移动要求;目前现役运载火箭测发控系统状态是系统复杂、难以移动,已不适应当前航天装备快速送入空间的发展,为此提出一种新型移动式测发控系统方舱结构模式;该模式采取了遵循设备集成原则,通过使用方舱、线缆铺设、人机工程优化等先进设计理念与方法来实现测发控系统快速、可移动的要求,同时解决了该系统原先存在多方面存在的问题;通过长期对系统方舱结构的研究工作,研发出通过采用“设备集成、线缆集中铺设、人机工程优化、方舱结构为平台”等先进技术的新型移动快速测发控系统方舱结构系统,为实现系统快速、可移动要求提供了技术基础;该系统经过工程使用,实现了新一代运载火箭快速简易测发控的目标。     

纵向耦合对垂直腔面发射激光器的影响

考虑到垂直腔面发射激光器中的光子与载流子的纵向耦合,在行波速率方程中引入了纵向耦合因子。利用这个速率方程,讨论了阀值电流与量子阱数目的关系,计算结果表明光子与载流子的纵向耦合是不容忽视的。给出了阀值电流表达式,它表明纵向耦合因子越大,阀值电流越低。     

透明导电薄膜ITO对浅面浮雕VCSEL的影响

对于顶面出光的浅面浮雕VCSEL结构,有源区的电流密度分布的不均性制约着单模稳定性的提高。为此,提出了一种新型结构:氧化铟锡透明导电薄膜(ITO)浅面浮雕VCSEL。该结构不仅能够增大高阶模式的阈值增益,还能够提高基模的增益,实现基模对高阶模式的稳定抑制。研究了ITO的厚度对阈值增益的影响及ITO对VCSEL有源区电流密度分布的影响。研究结果表明:在ITO的厚度为半波长的整数倍时,基模对高阶模式的限制作用最强;ITO通过改善VCSEL有源区的电流密度分布,达到了增大基模的增益和降低高阶模式增益的目的,同时还降低了串联电阻和外电压。     

深紫外激光光发射与热发射电子显微镜在热扩散阴极研究中的应用

对热扩散阴极表面微区发射状态进行原位观察和分析一直是热阴极研究的重要课题.本文着重介绍深紫外激光光发射电子/热发射电子显微镜的基本原理及其在热扩散阴极研究中的典型实例.系统配备了高温激活所用的加热装置,样品可被加热至1400℃.系统具有光发射电子、阴极热发射电子、光发射电子和阴极热发射电子联合三种电子成像模式.应用表明,对于热扩散阴极而言,深紫外激光光发射电子像适于呈现阴极表面的微观结构形貌;热发射电子像适于反映阴极表面的本征热电子发射及均匀性;光电子和热电子联合成像适于对阴极表面的有效发射点做出精确定位.     

Design of Two-Dimensional Photonic Crystal Edge Emitting Laser for Photonic Integrated Circuits

An edge emitting laser based on two-dimensional photonic crystal slabs is proposed. The device consists of a square lattice microcavity, which is composed of two structures with the same period but different radius of air-holes, and a waveguide. In the cavity, laser resonance in the inner structure benefits from not only the anomalous dispersion characteristic of the first band-edge at the M point in the first Brillouin-zone but also zero photon states in the outer structure. A line defect waveguide is introduced in the outer structure for extracting photons from the inner cavity. Three-dimensional finite-difference time-domain simulations apparently show the in-plane laser output from the waveguide. The microcavity has an effective mode volume of about 3.2（λ/nslab）^3 for oscillation mode and the quality factor of the device including line defect waveguide is estimated to be as high as 1300.     

Spectrum Simulation of Li-Like Aluminium Plasma

X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion （Al^9＋ and Al^11＋ ） charge states of the target ion （Al^10＋） are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.     

Characteristics of selective oxidation during the fabrication of vertical cavity surface emitting laser

Taking into account oxidation temperature, N₂ carrier gas flow, and the geometry of the mesa structures this paper investigates the characteristics of selective oxidation during the fabrication of the vertical cavity surface emitting laser (VCSEL) in detail. Results show that the selective oxidation follows a law which differs from any reported in the literature. Below 435℃ selective oxidation of Al_0.98Ga_0.02As follows a linear growth law for the two mesa structures employed in VCSEL. Above 435℃ approximately increasing parabolic growth is found, which is influenced by the geometry of the mesa structures. Theoretical analysis on the difference between the two structures for the initial oxidation has been performed, which demonstrates that the geometry of the mesa structures does influence on the growth rate of oxide at higher temperatures.