合肥先进光源储存环初步物理设计

我国最近立项建设的合肥先进光源将是一台软X射线与真空紫外衍射极限储存环光源,其电子束能量为2.2 GeV,周长为480 m,束流自然发射度为86 pm·rad,共有20个长直线节和20个短直线节。介绍了目前合肥先进光源储存环物理设计的进展情况,包括磁聚焦结构设计与优化,束流注入和集体效应的模拟与计算。     

可多重聚焦电磁能量的左手材料结构

 功分器在微波工程中广泛应用。基于有损耗的Lorentz模型的时域有限差分(FDTD)方法,分析模拟了左手材料(LHM)的平板结构和环状结构对电磁波源的不同聚焦特性。每个左手材料边界均可以对波源发出的波进行聚焦。同时通过比较,在对称结构中,每个聚焦点的电磁场幅度都相同。说明该左手材料结构可以对电磁波源进行多点聚焦。     

强流脉冲离子束烧蚀等离子体向背景气体中喷发的数值研究

强流脉冲离子束辐照靶材产生烧蚀等离子体向背景气体中传播与向真空中传播不同，包括喷发等离子体与背景气体的相互作用.本文建立了该过程的二维气体动力学模型，计算了等离子体向压强范围从10^-6大气压到大气压背景气体中传播时的情况.结果表明，背景气体压强不同时，等离子体传播的现象也不相同.向真空中可以自由膨胀，向大气压中膨胀受限；当背景气压在千分之一大气压左右时，等离子体在背景气体中形成“雪犁”状，羽状等离子体出现快速和慢速传播分离现象.     

双离子束溅射淀积DLC膜的红外特性

用双离子束溅射法在50℃以下的玻璃基片上淀积了类金刚石碳(DLC)膜.研究了轰击离子能量、轰击离子束流密度及轰击源内氢/氩流量比例对淀积片红外透射特性的影响.所用波段是1.5～5.5μm.结果表明,对所有淀积样片,其相对透过率均随波长增长而增大.在每组实验中,随如上各可变参量的增大,各样片的相对透过率～波长曲线均有先上升后下降的规律.确定了各组相应的临界参数.结果还表明,轰击源不含氢并不影响DLC膜的制取,但轰击源合氢时所制得的膜具有更好的红外透射性.从结构变化的角度解释了上述规律.     

离子束溅射Ge量子点的应变调制生长

采用离子束溅射技术制备了单层和双层Ge量子点, 通过原子力显微镜对比了不同Si隔离层厚度和不同掩埋量子点密度情况下表层量子点的尺寸和形貌差异, 系统研究了掩埋Ge量子点产生的应变对表层量子点的浸润层及形核的影响, 并用埋置应变模型对其进行解释. 实验结果表明, 覆盖Ge量子点的Si隔离层中分布着的应变场, 导致表层量子点浸润层厚度的降低, 从而增大点的体积; 应变强度随隔离层厚度的减小而增加, 造成表层量子点形状和尺寸的变化; 此外, 应变还调控了表层量子点的空间分布. 关键词： Ge量子点 埋层应变 离子束溅射     

Uptake of transferrin-conjugated quantum dots in single living cells

We study the uptake and distribution of transferrin （Tf）-conjugated CdSe/CdS/ZnS quantum dots （QDs） in single living HeLa cells with both fluorescence confocal microscopy and three-dimensional （3D） reconstruction technique. By increasing the co-incubation time or the dosage of QDs-Tf, we find that the uptake of QDs-Tf bioconjugates in the cells increases correspondingly, but with different uptake rates. Additionally, the distribution of QDs-Tf, in single live HeLa cells is time dependent. To our knowledge, this is the first study on quantitatively analyzing the uptake and distribution of bioconjugated QDs in single living cells. Such QDs nanoplatform can be further modified for developing biomedical evaluation tool in cancer diagnosis and targeted drug delivery.     

硒化锌基底2～16μm超宽带硬质红外增透膜的研制

硒化锌材料具有较宽的透光区,使其在红外区有着广泛的应用,然而其作为基底,镀制超宽带增透膜却有相当大的难度,尤其是膜层强度问题。设计出了硒化锌基底上2～16μm的多层超宽带增透膜,并采用离子束辅助沉积工艺在硒化锌基底上进行了多次实验,并对所使用的氟化钇(YF_3)和硒化锌膜料进行了分析,发现YF_3在3400和1640 cm~(-1)两个波数处的吸收峰。通过将低折射率层改为氟化钡和氟化钇的组合层后,在硒化锌基底上成功镀制出了多层宽带增透膜并采用脉冲电弧离子镀技术在多层薄膜的表面镀制了一定厚度的类金刚石(DLC)薄膜,增强了膜层的强度。最终使硒化锌基底上镀制的超宽带增透膜在2～16μm范围内的平均透射比大于93%,峰值透射比大于97%,并且膜层的强度较好。     

Detection of subsurface defects of fused silica optics by confocal scattering microscopy

<正>A non-destructive technique for subsurface measurements is proposed by combining light scattering method with laser confocal scanning tomography.The depth and distribution of subsurface defect layers are represented in term of scattered light intensity pattern,and three types of fused silica specimens are fabricated by different grinding and polishing processes to verify the validity and effectiveness.By using the direct measurement method with such technique,micron-scale cracks and scratches can be easily distinguished,and the instructional subsurface defect depths of 55,15,and 4μm are given in real time allowing for an in-process observation and detection.     

Surface plasmon interference formed by tightly focused higher polarization order axially symmetric polarized beams

We numerically study the surface plasmon interference formed by tightly focused higher polarization order axially symmetric polarized beams (ASPBs) based on the vectorial diffraction theory. The definition of ASPBs is stated, and the optical setup for surface plasmon polariton (SPP) excitation and mathematical expressions for interfering SPP fields are proposed. The simulation results show that the interfering SPP fields present a multi-focal spot pattern. In addition, the number of spots is related to the polarization order of the incident beams P as 2×(P-1), indicating potential utilization in near-field multiple optical trapping and near-field imaging and sensing. The unique interfering phenomenon is also explained.