用于磁旋转光谱的环形永磁阵列的匀场分布仿真优化

法拉第磁旋转光谱(Faraday rotation spectroscopy, FRS)技术因其高灵敏度,零背景噪声,以及能有效避免抗磁性物质干扰的特性广泛应用于各类顺磁性痕量气体的探测.目前大部分FRS技术采用线圈构造电磁场,存在能耗高、发热多等问题.为此,开展了基于组合环形永磁体的空间磁场分布建模仿真研究,意在建立轴向分布的磁场,为测量FRS提供基于永磁体的沿光轴方向的匀强磁场.仿真采用有限元网格剖分的方法,基于麦克斯韦方程组,开展组合磁环的磁场分布仿真研究,并通过实验测量实际钕铁硼永磁体磁环阵列的磁场分布,证明了建立物理模型的可靠性.在此基础上提出了对永磁体磁环阵列的3种优化方案—单理想值优化、多段式单理想值优化和梯度优化方案,来构造中心轴线磁感应强度分布均匀的匀强磁场.最后通过引入磁场均匀度,计算评估并分析比较了不同优化方案的优化效果,为研发基于永磁体的FRS光谱设备提供参考.     

10.6μm玻璃-金属复合波导激光器的偏振特性

提出一种使小型波导CO_2激光器产生线偏振光输出的波导管结构,在激活介质长度250mm、总腔长310mm的条件下,获得功率大于5W、偏振度大于95％的线偏振TEM_(00)模激光输出。     

医用波导CO2激光器

本文报导一种符合医用要求的新型玻璃波导CO2激光器。该器件采用大孔径玻璃波导（d=3～4mm）。提出近场非匹配凹面镜选模的新方法和整体冷却管体的新结构。激光器全长310mm时，能得到输出功率8W左右的稳定基模。连续工作寿命大于1000小时。     

Se substitution and micro-nano-scale porosity enhancing thermoelectric Cu_2Te

Binary Cu-based chalcogenide thermoelectric materials have attracted a great deal of attention due to their outstanding physical properties and fascinating phase sequence.However,the relatively low figure of merit z T restricts their practical applications in power generation.A general approach to enhancing z T value is to produce nanostructured grains,while one disadvantage of such a method is the expansion of grain size in heating-up process.Here,we report a prominent improvement of z T in Cu_2Te_(0.2)Se_(0.8),which is several times larger than that of the matrix.This significant enhancement in thermoelectric performance is attributed to the formation of abundant porosity via cold press.These pores with nano-to micrometer size can manipulate phonon transport simultaneously,resulting in an apparent suppression of thermal conductivity.Moreover,the Se substitution triggers a rapid promotion of power factor,which compensates for the reduction of electrical properties due to carriers scattering by pores.Our strategy of porosity engineering by phonon scattering can also be highly applicable in enhancing the performances of other thermoelectric systems.     

Self-focusing of partially coherent beams based on complex screen and split-step Fourier transform methods

The self-focusing phenomenon of partially coherent beams(PCBs) was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schr?dinger equation. Considering the propagation of Gaussian Schell-model beams in a nonlinear medium as an example, the suppression effects of intensity, propagation distance, and spatial coherence on small-scale self-focusing were demonstrated. Simulations of overall and small-scale selffocusing using this method were c...     

圆波导激光器的腔片倾斜损耗

对采用平面反射镜的圆波导激光器的耦合情况进行了分析,提出腔镜倾斜引起损耗的计算模型,得到倾斜损耗的计算解析式和曲线。并对计算过程中取近似所忽略的部分也作了定量讨论,指出这种近似是可容许的。