Investigation of the nonlinear CPT spectrum of ~(87)Rb and its application for large dynamic magnetic measurement

The coherent population trapping(CPT) phenomenon has found widespread application in quantum precision measurements. Various designs based on the narrow resonant spectrum corresponding to the linear Zeeman effect have been demonstrated to achieve high performance. In this article, the nonlinear Zeeman split of the CPT spectrum of ~(87)Rb in the lin||lin setup is investigated. We observe re-split phenomenon for both magnetic sensitive and magnetic insensitive CPT resonant lines at a large magnetic field. The re-split in the magnetic sensitive lines raises a practical problem to magnetometers worked in the lin||lin setup while the other one shows a good potential for applications in large magnetic field. We propose a design based on the nonlinear split of the magnetic insensitive lines and test its performance. It provides a much larger measurement range compared to the linear one, offering an option for atomic magnetometers where a large dynamic range is preferred.     

Tuning the velocity and flux of a low-velocity intense source of cold atomic beam

We investigate experimentally and numerically the quantitative dependence of characteristics of a low-velocity intensity source(LVIS) of atomic beam on light parameters, especially the polarization of cooling laser along the atomic beam axis(pushing beam). By changing the polarization of the pushing beam, the longitudinal mean velocity of a rubidium atomic beam can be tuned continuously from 10 to 20 m/s and the flux can range from 3 × 10~8 to 1 × 10~9 atoms/s, corresponding to the maximum sensitivity of the velocity with respect to the polarization angle of 20(m/s)/rad and the mean sensitivity of flux of 1.2 × 10~9(atoms/s)/rad. The mechanism is explained with a Monte-Carlo based numerical simulation method, which shows a qualitative agreement with the experimental result. This is also a demonstration of a method enabling the fast and continuous modulation of a low-velocity intense source of cold atomic beam on the velocity or flux,which can be used in many fields, like the development of a cold atomic beam interferometer and atom lithography.     

压电致动微喷的压力波特征分析

提出了一种压电致动的阵列微喷 ,以面向吸入式药物治疗应用。该阵列微喷工作在器件的谐振点上 ,其工作性能决定于液体腔中的压力波的分布和大小。本文针对该类微喷建立了考虑压电 固 液耦合和压力波传播效应的等效模型 ,并利用有限元方法对整个器件的结构振动模态和压力驻波模态进行了分析。文章对不同振动模态下 ,液体腔中的声压力波分布以及对微喷设计的影响进行了讨论     

MEMS微梁静电致动器的力学特性研究

采用降阶建模法对多晶硅／氮化硅复合悬臂粱静电致动器的多物理场耦合问题进行了仿真计算。悬臂粱在氮化硅残余应力的作用下弯曲翘起。在微粱和基底间施加电压后，微粱受到向下电场力的作用，当电压超过阈值后微粱就会被吸到基底上。通过提取系统的各阶模态及其对系统的贡献，对各阶模态进行组合来取代该结构的耦合域，从而达到对耦合问题降阶的目的。采用该方法算得微粱的翘起高度、1阶固有频率和吸下的阚值电压与实验测得的结果吻合较好。     

利用原子干涉仪的相位调制进行绝对转动测量

提出一种基于原子干涉仪的相位调制进行绝对转动测量的方法.以π/2-π-π/2构型的空间型原子干涉仪为例，通过对拉曼激光进行相位调制，然后在动量谱空间测量转动对原子速度谱的调制周期，获得原子干涉仪相对惯性空间的绝对转动.文章对于采用该法进行角速度测量的测量范围以及对相位调制频率的要求进行了分析，对于散粒噪声限下的转动测量灵敏度及其影响因素进行了仿真.     

微系统与纳系统技术（下）

三 纳系统技术 纳系统,或称NEMS,其关键特征尺度在几百到几纳米,它包括纳结构、纳器件和纳系统以及纳米尺度的测控和制造技术等,是纳米技术发展的最终目标之一。与微系统不同,纳系统是以小尺度为特征的,也就是说,纳器件和系统的性质和行为可能是由小尺度所     

Widely tunable laser frequency offset locking to the atomic resonance line with frequency modulation spectroscopy

A simple and robust technique is reported to offset lock a single semiconductor laser to the atom resonance line with a frequency difference easily adjustable from a few tens of megahertz up to tens of gigahertz. The proposed scheme makes use of the frequency modulation spectroscopy by modulating sidebands of a fiber electro-optic modulator output. The short-term performances of a frequency offset locked semiconductor laser are experimentally demonstrated with the Allan variance of around 3.9 × 10~(-11) at a 2 s integration time. This method may have many applications, such as in Raman optics for an atom interferometer.     

一种基于介质上电润湿效应的免疫检测芯片研究

利用微机械加工技术,在ITO玻璃上设计制作了基于介质上电润湿效应的以离散液滴为对象的免疫检测芯片,对芯片的液滴驱动特性、免疫反应参数进行了测试,并对小鼠IgG和羊抗鼠IgG-HRP进行了初步的免疫测试.研究结果表明,在电压<100 V的时候,接触角测量值基本上和预测曲线吻合,在>100 V的情况下出现了接触角饱和现象,在芯片上实现了液滴操纵,120 V时得到最大平均速度为3.75 mm/s;该芯片可以实现免疫反应检测,所需样品体积为0.5 μL,检测时间约为20 min,对于羊抗鼠IgG-HRP实验系统的检测范围为0.1～20 mg/L.     

微系统与纳系统技术（上）

微系统(Micro Systems)和纳系统(Nano Systems)是微米纳米技术最终开发目标之一,是21世纪技术发展的热点。作为IC的扩展和大规模微结构器件在小空间中的高度集成,我们的读者在陌生中可能会感到一丝熟悉。     

压电驱动阵列微喷的加工及实验研究

介绍了一种基于微电子机械系统（MEMS）技术的阵列微喷的加工和实验结果。利用微细加工技术，在硅片上制作了上千个直径够5～20μm的微喷孔阵列。该微喷以压电效应为驱动方式，通过压电片振动所产生的压力使液体从微喷孔中喷出。具有所产生的液滴直径和速度分布集中，无热效应的特点。采用激光相位-多普勒粒子分析（PDPA）系统对不同工作条件下液滴的直径和速度进行了研究。