中能重离子微束辐照装置的真空窗

为了辐照生物活细胞, 束流须经由真空隔离窗引入大气环境中. 在真空隔离窗的设计中, 对结构、材料种类及其厚度的选择既要尽可能地减小束斑展宽, 又要兼顾安全性. 应用有限元分析软件对不同结构、不同材料的真空窗进行受力分析, 模拟真空窗的形变和等效应力, 运用强度理论考察候选真空窗的安全性; 并运用SRIM程序模拟离子的小角散射、横向射程, 计算入射离子的能量、真空窗材料及其厚度、空气层对束斑展宽的影响; 最后提出真空窗适宜的结构、材料及厚度范围.     

用于光电检测的高精度任意波形光信号源技术研究

光作为信息的有效载体,现在已经在通信、工业控制、国防等领域得到广泛运用。在许多领域,提供实际检测的光信号存在一定的困难,同时仿真信号比实际信号具有误差小、便于量化分析等优点。从光源的选择,驱动电路的设计和通过适当的数据变换等几方面考虑,设计出了一套精密的光信号源发生器。实验结果表明,该系统能够使LED在保持P-I曲线不变的情况下,实现光功率的线性输出。     

高精度光链路授时时延估算

授时系统中信号单程传输时延的估算直接影响到授时的精度, 环路时延测试是估算单程传输时延的方法之一。在光缆授时系统中光纤的色散特性将导致不同波长光信号在同一光链路中的传输时延存在差异, 基于G.652光纤的色散特性, 提出的时延差精确估算方法, 能够得到这种传输时延的差异。仿真显示来回链路工作波长在1.55 μm附近时, 此方法能够很好地补偿时延差, 从而精确估算信号传输时延。     

微腔光梳的产生、发展及应用

光频梳提供了光波和微波相干链接的桥梁,它的诞生革命性地提高了人们对于光学频率和时间的测量精度,深刻影响着当今世界科技的发展.最早的光频梳产生于锁模激光器系统,然而基于锁模激光器的光梳,因其系统复杂、体积庞大和价格高昂,一般仅限于实验室应用.近年来一种新型光频梳应运而生,并有望解决上述问题.它是通过连续激光耦合进入高品质光学微腔而激发的,在频域上通过四波混频产生等间距的频率分量,在时域上则利用非线性效应平衡微腔色散而形成锁模,这种新型光频梳被称为“微腔光梳”.相比于传统光梳,微腔光梳有着尺寸小、可集成、功耗低和重频范围大等优势,它的出现标志着产生光梳迈向芯片级尺寸的时代,并引起了科学界和工业界越来越多的关注.本文首先概述了微腔光梳的产生与发展历程,随后介绍微腔光梳在实际应用方面取得的进展,最后对微腔光梳当前的问题进行总结,并对未来发展进行展望.     

采用正弦微窗光栅的位移传感器

研制了一种新型的光栅位移传感器,它采用了一种被作者称为正弦微窗光栅的新元件作为指示光栅,用于消除光栅信号中的高次谐波,所为正弦微穿光栅是一种由许多微小的正弦穿孔排列组成的光栅。介绍了采用光学图形发生器和刻蚀镀膜工艺制造这种光栅的方法。并将制成的正弦微穿光栅用于光栅位移传感器的设计。实验表明,新型传感器能够很好地抑制光栅信号中的高次谐波,可将高次谐波总旧降至基波的２％以下。     

激光陀螺光电探测器光窗的设计

用平面波计算拍频条纹间距时,因激光器中存在衍射效应,且实际光强分布为高斯型,故给光电探测器光窗尺寸计算带来很大误差(40%),导致系统不能正常工作。为此,以高斯光束为基础,利用光电探测器测得2路信号的相位差,通过数值计算得到2束光拍频条纹间距,由此计算得到理想相位差光电探测器的尺寸。最后,用实验验证了该设计方法的可行性,为RLG光电探测器光窗尺寸的设计提供了一种简单准确的方法。     

弯曲导管束在“水窗”及附近软X光的响应测量

测量了弯曲导管对“水窗”波段及其附近的X光响应,圆弧弯曲导管束对X光在“水窗”段有较大传输效率,而对“水窗”之外的高能X光响应较小,研究表明,X光在“水窗”段的响应,可以是在“水窗”之外的高能X光的响应的5倍,这种弯导管有可能用于同步辐射中,“过滤”掉白光高能部分,而直接输出较强的“水窗”段X光.     

激光高精度细胞微手术机理的研究

激光微手术的精度通常受到热作用或者热机械效应间接损伤的限制。把激光脉宽调整到与吸收颗粒的热弛豫时间一致可以避免热副作用,可对所选细胞产生选择性处理。这里胶体金与牛肠硷性磷酸脂酶（Alkaline phosphatase,AP）结合物作为分析强吸收颗粒附近的蛋白质变性的模型系统,利用皮秒和纳秒激光对结合体进行照射,在一定的条件下可以使蛋白质失活,并可以使细胞膜的通透性提高。通过计算可知,采用脉宽为皮秒或者纳秒级的激光照射纳米吸收物（胶体金）时,颗粒很容易被加热到几百开,而且热效应仅限于几十纳米的空间范围内。利用纳米吸收颗粒进行激光微手术的方法．在蛋白质失活的情况下对其机弹讲行了分析．     

激光快速成型技术研究

激光快速成型技术由于其广范的应用前景而得到广泛深入研究^1,2,本文重点讨论我们研究所设计的激光快速成型系统的关键技术及其应用新领域逆工程．     

锗窗片的光学加工技术

加工平行平面锗窗片,采用双面研磨法修改平行度,用吸附方法粘结成盘,固着磨料抛光模粗抛,沥青抛光模精抛,解决了批量生产中等精度(平行度等于1!@)锗窗片的加工工艺。该工艺也适用于其他晶体材料的平面加工。     

Fixed energy balance window quench correction for high precision LSC C dating

In this paper we present the new LSC spectra evaluation method for high precision ¹⁴C dating with Quantulus 1220™. The generally used fixed window is replaced with the fixed energy balanced counting window. The lower and upper channel of the window in the multichannel analyzer vary according to the quench level of each individual measurement. The position of the window is determined with the external standard quench parameter SQP(E) of Quantulus 1220™. We show how this fixed energy balance window for each sample secures high stability and reduced quench correction. This method is compared with the typically used fixed channel window.     

Micro traps for quantum information processing and precision force sensing

We review recent experimental progress towards quantum information processing and precision force sensing using neutral atoms in micro traps. Microscopic potential structures as generated by optical or electronic microstructures (micro traps) allow for a versatile manipulation of quantum states of atoms and of ultracold atomic quantum gases. Most recent experimental results include the implementation of single‐qubit‐operations in both, optical and magnetic micro traps, as well as in the demonstration of matter‐wave interferometer using Bose‐Einstein condensates coherently split in micro traps.     

Positron trapping measurements of high precision using a labelling technique

The small effects associated with positron trapping in metal defects are masked in practice not only by inherent statistical fluctuations, but also by electronic instabilities. the unique directional correlation of annihilation quanta allows us to use a very efficient labelling technique which facilitates simultaneous measurements of the annihilation energy spectrum in the sample and in a standard. The result is that the system becomes essentially free of drift, so that precision of energy determination is limited by the statistics of counting alone. We have used the efficient technique of Ge(Li) spectroscopy together with labelling to measure the annihilation lineshape. Lineshape parameters, including the first two moments, have been extracted from this data. The techniques are applied to the measurement of recovery at room temperature and to a determination of the binding energy of positrons to traps in aluminum. Paper B 25 presented at 3rd Internat'l Conf. Positron Annihilation, Otami, Finland (August 1973).     

多束高重复频率全光纤激光脉冲时间波形实时精密测量技术

提出了一种基于时分复用的多束高重复频率全光纤激光脉冲时间波形实时精密测量技术,针对分类成组的多束高重复频率全光纤激光系统不同测量功能需求,分别设计了1×8时分复用器、不同延时量的1×2时分复用器,实现了48路、144个1kHz光纤激光整形脉冲时间波形宽度、上升沿、面积等关键参数的精密测量,同时实现了多束高重复频率全光纤脉冲激光系统运行状态的实时监测。     

多束高重复频率全光纤激光脉冲时间波形实时精密测量技术

提出了一种基于时分复用的多束高重复频率全光纤激光脉冲时间波形实时精密测量技术,针对分类成组的多束高重复频率全光纤激光系统不同测量功能需求,分别设计了18时分复用器、不同延时量的12时分复用器,实现了48路、144个1 kHz光纤激光整形脉冲时间波形宽度、上升沿、面积等关键参数的精密测量,同时实现了多束高重复频率全光纤脉冲激光系统运行状态的实时监测。     

Optimization for high precision Shack-Hartmann wavefront sensor

A comprehensive noise model about digital camera which is a main component of SHWFS is constructed, including the readout noise, the photon shot noise, the quantization noise and the response un-uniformity. Based on the noise model, the spot centroid errors caused by each kind of noise are analyzed, respectively. And then the synthetic error from all the noise is calculated. The result demonstrates that the limit of the spot centroid accuracy is 1% pixels. At last, the crossing error caused by the high order diffraction spots is analyzed. It is approximately proportional to the secondary spots number. So the structure of the microlens array must be optimized together with the digital camera when designing SHWFS.     

Micro cooling systems for high density packaging

Future 3D electronics packaging systems will require micro cooling systems that can be integrated and permit the continued use of air as a coolant. To achieve this, new types of silicon micro heat exchangers were made using an anisotropic etching process. Various heat exchanger configurations and sizes were made using sandwich and stacking techniques. They can be used either as a heat exchanger for direct cooling with compressed air or as a heat pipe and thermosyphon for indirect cooling with fan-blown air. The performance characteristics of the various cooling systems are stated. The micro-heat-pipe can be used for power loss densities of up to 3 W·cm⁻², the direct air cooling up to 15 W·cm⁻² and the thermosyphon up to 25 W·cm⁻². Cooling performances are achieved that are otherwise only possible with liquid cooling. The practical application of the micro cooling system is demonstrated using the example of the Pentium processor. With a power loss of 15 W, the high-performance micro cooling system is able to limit the increase in operating temperature to 15 K. The volume of the micro heat exchanger is 2.5 cm³ and therefore considerably smaller than that of standard heat sinks.     

Micro via and line patterning for PCB using imprint technique

Today’s electronic devices such as mobile phones, PDA, computers, etc. have more functions in a smaller size. Thus conducting lines and via holes of PCB (printed circuit board) which has a role of land for all kinds of electronic components are getting finer. In this study, the conducting lines and via holes are produced using thermal imprint technique rather than the conventional photo-lithography process. Imprint technique is a press process that transfers patterns of stamp to resins. Imprint technique is used to produce micro size trench lines and via holes in epoxy resins.Resins used in this work are silica (SiO₂) reinforced epoxy. Resins were imprinted using 10 * 10 mm size Ni or polymer stamp. Line/space of pattern is 10/10 μm while diameter of via hole is 30 μm. The depths of lines and via holes are 15 and 30 μm, respectively. The anti-sticking treated stamp and epoxy resins were pressed at 100 °C for 30 min in vacuum. The stamp was released after resins were cured for 1 h at 130 °C. All patterns of stamp were successfully transferred with high fidelity and any noticeable defect was not observed within imprinted area. Imprinted resins were de-smeared to remove the residue at the bottom of via holes and to enhance the adhesion of resins with Cu. Electro/less copper plating was followed to fill in the imprinted patterns. Since the excess Cu layer was formed on the resins during Cu plating, the planarization process was introduced to obtain isolated lines and via holes.     

Design for high precision and off-axis compact collimation system

An off-axis reflective collimation system design for application in Radar systems is presented. The cross-section of the system has a round configuration for compactness. Based on the spatial analytic geometry and the reflection law (in vector form), space propagation rules for laser beam are derived. The optical design is simulated and optimized using MATLAB. The highly collimated results are presented.     

MEMS profilometry by low coherence phase shifting interferometry: Effect of the light spectrum for high precision measurements

A white light interferometer can be used to measure profiles of a few nanometers and is therefore particularly well adapted for micro electro mechanical systems characterization. We present theoretical and experimental results on the profile precision as a function of the light source spectrum. We demonstrate that even if a broadband source is used in the phase shifting mode, the knowledge of the light spectrum allows to calculate a correction factor. This factor determines the local effective wavelength and can be used in order to increase the measurement precision of sample profiles.