Optimal Design of Multilayer Mirrors for Water-Window Microscope Optics

A small bandwidth of periodic multilayers at wavelengths 2.4–4.4 nm presents problems for the spectral matching of mirrors. This leads to low throughput of a Schwarzschild microscope and its sensitivity to technological errors in layer thickness. We consider two cures for these difficulties: aperiodic coatings and a lateral gradient of layer thickness. Our design of aperiodic multilayers maximizes the throughput of a microscope made at a fixed level of technology. The method includes a new merit function, fast procedure for its minimization, linkage between multilayers and an equation for a lateral gradient of layer thickness. Computation is performed for Sc/Cr coatings at 398 eV. It shows that the aperiodicity makes optics stable to technological errors, while the lateral gradient increases throughput, but enhances sensitivity to the errors. The best results are obtained for aperiodic mirrors with a lateral gradient of thickness, which assure both high microscope throughput and stability to the errors.     

3D Particle Tracking on a Two-Photon Microscope

A 3D single-particle-tracking (SPT) system was developed based on two-photon excitation fluorescence microscopy that can track the motion of particles in three dimensions over a range of 100 μm and with a bandwidth up to 30 Hz. We have implemented two different techniques employing feedback control. The first technique scans a small volume around a particle to build up a volumetric image that is then used to determine the particle's position. The second technique scans only a single plane but utilizes optical aberrations that have been introduced into the optical system that break the axial symmetry of the point spread function and serve as an indicator of the particle's axial position. We verified the performance of the instrument by tracking particles in well-characterized models systems. We then studied the 3D viscoelastic mechanical response of 293 kidney cells using the techniques. Force was applied to the cells, by using a magnetic manipulator, onto the paramagnetic spheres attached to the cell via cellular integrin receptors. The deformation of the cytoskeleton was monitored by following the motion of nearby attached fluorescent polystyrene spheres. We showed that planar stress produces strain in all three dimensions, demonstrating that the 3D motion of the cell is required to fully model cellular mechanical responses.     

全介质镜微腔的结构设计与发光特性的模拟

设计了4种不同介质镜结构的全介质镜λ微腔,并模拟研究了腔内有机发光层的发光特性。结果表明,DBR结构的不同会导致腔镜反射相移的变化,从而最终改变了器件的透射光谱、腔内驻波电场分布、PL光谱峰值位置和强度等参数。只有合理的器件结构设计才能使腔内的发光得到有效的增强。对称偶数层DBR构成的λ腔可以使谐振峰位置的PL光谱峰值强度增加59倍。     

同步双转镜调Q激光器

用双转镜装置这种最简单、有效的方法，实现了调Q激光输出，得到了平缓、光滑的脉冲，大大改善了以往转镜调Q激光器的不足。     

Scheme for Entangling Two Distant Cavity Mirrors

A scheme is presented for the generation of entangled states for two cavity mirrors. In the scheme each mirror initially in a vacuum state interacts with a weak coherent field, resulting in a photon-number dependent kick. The detection of a photon leaking from the cavities collapses the two mirrors to an entangled state.     

基于GPU加速的磁共振血管造影图像的并行分割与追踪算法

在应用磁共振血管造影图像进行临床诊断时,临床医生往往需要提取感兴趣区域(Region Of Interest,ROI)的部分血管.这个工作传统上需要手工进行,费时费力.该文提出一种并行的血管分割与追踪算法,利用现代图形处理器(Graphics Processing Unit,GPU)所具备的大规模并行计算能力进行快速的血管分割.首先将三维图像网格化为共面的立方体,并行处理每个立方体,确定立方体中哪些表面有血管通过,以及立方体中哪些体素包含血管.之后再将该结果用于串行的全局分割与血管追踪处理.实验结果表明,利用这种先并行后串行的方法,可以在1 s之内完成全脑血管的分割,分割的结果也更准确.     

Analysis of a Fiber Laser with Two Nonlinear Amplifying-Loop Mirrors

We present the results of the analysis of a fiber laser containing two nonlinear amplifying-loop mirrors (NALM). With the theoretical analysis we have developed, we were able to extend the analysis of a figure of eight laser (F8L) to the case of a similar structure with two NALM. Using the split-step Fourier method we have determined the influence of each NALM coupling ratio on the performance of the laser. We obtain a reduction in the fiber amplifier gain needed to initiate the oscillation as a consequence of this new configuration. Results also show that an optimum combination of the two NALMs' parameters is possible for given optical power and width of the generated pulses.     

Two Beam Collection Mode Photon Scanning Tunneling Microscope

We studied the image deformation due to the surface inclination of objects in photon scanning tunneling microscopes (PSTM). A novel collection mode PSTM with two light sources is proposed to reduce the deformation and experimental results show that the PSTM system is effective.     

基于线扫描成像的光片荧光显微镜

设计了一种基于线扫描成像(LSI)的光片荧光显微镜(LSFM),旨在通过抑制样本散射达到提高成像质量的目的 .该显微镜将数字扫描光片荧光显微镜(DSLM)与LSI两种方法结合,以前者为基础,在探测光路上增加了一个用于解扫描的扫描振镜.在控制过程中,将照明光路的扫描振镜与解扫描振镜同步,使得均匀运动的图像在相机前固定于同...     

基于LabVIEW的显微镜自动控制设计

为方便CCD相机采集显微镜下的图像,对显微镜的控制进行了研究。设计了一种实现显微镜自动控制的方法。利用THB6128芯片驱动步进电机实现焦距的电控调节,利用PT4115芯片控制LED灯实现照明灯光亮暗的调节,基于labVIEW虚拟仪器平台开发主控制程序搭建外围硬件,实现显微镜的自动控制。实验证明,上位机运用程序通过串口进行数据通信向下位机发送指令,通过调节LED灯的亮暗以及步进电机转动带动载物台的上下移动,实现了在一个合适的光照和焦距下获取清晰的图像。使显微镜控制更加的简化与精确,便于图像的采集。     

基于绝缘体上的硅材料的全内反射型阵列波导光栅器件的设计

设计了一种基于绝缘体上的硅材料的全内反射型阵列波导光栅解复用器年。将一全内反射波导镜引入原弯曲的波导列阵中，该波导镜具有偏振补偿的功能和缩小器件尺寸的特点。在器年数值模拟的基础上，制作了原理性器件，并获得了初步的实验结果。     

Formation of Magnetic Nanostructures Using an Atomic Force Microscope Probe

Technical Physics - The examples of application of pulse force nanolithography carried out using an atomic-force microscope probe for formation of magnetic nanowires, nanocontacts, one- and...     

基于多层膜系传输矩阵理论的双啁啾镜设计与实验

把光在多层膜中传输的矩阵理论应用于双啁啾镜的设计。理论分析结果表明设计的双啁啾镜可以对波长从600 nm到1 100 nm波段范围的色散进行补偿,每次可以实现-100 fs2的色散补偿量,而且双啁啾镜可以有效降低单镜色散补偿中的寄生振荡。用设计制造的双啁啾镜进行了实验测试,用双啁啾镜对畸变脉冲进行色散补偿,实验结果表明:经过两次色散补偿可以将脉冲还原至初始状态,而过量的负色散又将脉冲重新展宽。     

静态傅里叶变换红外光谱仪的公差分析

由于光谱分辨率或光谱信噪比只能作为光谱仪干涉系统的性能评价指标,但不能用于光学系统的公差分析与优化,所以将系统分为三个子系统:前置光学系统、干涉系统与后置光学系统,分别采用不同的评价标准分析系统公差。前置光学系统采用波像差为评价标准,给出波像差与光谱噪声的关系,分析误差对波像差的影响,间接给出各种误差对系统性能的影响。干涉系统直接采用光谱噪声作为评价标准,可直接给出各种误差对系统性能的影响。后置光学系统采用光斑尺寸作为评价标准。通过这种方法,计算出三个子系统的灵敏度矩阵,并且给出了前置光学系统与后置光学系统的公差分配。     

Influence of the Magnetic Moment of the Probe of a Magnetic Resonance Force Microscope on the Spin-Wave Resonance Spectra

Physics of the Solid State - Abstract—The ferromagnetic resonance in an array of permalloy microstrips 3000 × 500 × 30 nm3 in size, which are ordered on a rectangular 3.5 × 6...     

Experimental Study of a Fourier Transform Spectrometer Based on Scanning Micro-Electromechanical Mirrors

This paper presents a non-scanning Fourier transform spectrometer based on a micro-electronic mechanical system micro-mirrors and a single detector. The fundamental principle and key parameters of this Fourier transform spectrometer were analyzed in detail. Theoretical analysis showed that, when the dip angle of the slantwise mirror is 0.38713°, the resolution of the system is 9.7 nm (at 1350 nm). Experiments demonstrated that, the spectra resolution is less than 10 nm, the wavelength deviation is ～1.5 nm, the signal-to-noise ratio is higher than 30 dB and the intensity deviation at peak wavelength is less than 0.4%.     

Spontaneous Emission of a Polarized Atom in a Medium Between Two Parallel Mirrors

Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.     

Extracting Oscillation Frequencies in Spontaneous Emission Rate of an Atom Between Two Mirrors

For an atom in a medium with refractive index n sandwiched between two parallel mirrors, we derive an analytical formula for the spontaneous emission rate based on Fermi＇s golden rule. The oscillations are not transparent in this formula. By performing Fourier transform on scaling variable measuring system size while holding system configuration fixed, we extracted the frequencies of many oscillations in this system. We show that these oscillations correspond to emitted photon closed-orblts going away from and returning to the emitting atom.     

基于多处理器的视频跟踪系统研究

传统视频跟踪系统的目标检测环节常采用手动指定或使用单处理器运算来确定跟踪目标,这种方法耗费人力且检测速度慢。针对此问题提出了一种改进的图像分割方法,该方法采用多处理器系统构架,并行处理分割区域,增加了检测目标的速度,并且在后续目标跟踪环节中,各处理器根据任务划分,协同处理跟踪任务。实验结果表明基于多处理器系统构架的视频跟踪系统能够实现快速自动检测与跟踪目标,系统加速比为2．066,处理器效率为51．65％。