基于微力传感的扫描近场声显微镜

描述了一种用于检测超精表面形貌的扫描近场声显微镜 (SNAM )。以谐振频率为 1MHz的未封装伸长型晶振作为微力传感器逼近样品表面 ,在此过程中晶振受到流体阻尼 ,其振动特性发生变化 ,通过检测振动幅值的变化即可获得样品表面形貌信息。在分析SNAM检测机理的基础上设计了SNAM系统 ,测量时的垂直分辨率可达到纳米级     

一种数控工作台的设计

本文介绍了一种采用微机控制,步进电机驱动的数控工作台,实现了平面两坐标数控联动。     

一种用于光纤F-P传感器的微纳米级微位移工作台的研究

标定光纤F-P传感器这种微纳米级位移传感器非常困难。分析常用的微位移技术优缺点，这里提出了一种基于弹性变形原理的工作台的设计方法。建立了工作台位移变形的数学模型，对其产生位移的误差进行了理论分析。在此基础上，实际设计并开发了实验系统，用德国heidenhaiyn光栅位移传感器对光纤F-P传感器进行了标定实验。大量的标定实验证明，该微位移工作台的不确定度为0．1μm。     

磁悬浮工作台形变对承载磁场力的影响分析

基于ANSYS有限元分析软件,对承载力为500N的磁悬浮工作台的形变对其支承电磁铁磁场力的影响进行了分析.分析结果表明:当悬浮气隙为0.3mm且工作台上、下支承电磁铁处的最大形变量△1和△2分别不超过0.02mm和0.01mm时,磁悬浮工作台的承载性能得到提高.将有限元分析软件应用于磁悬浮工作台的设计中,对提高其设计质量具有重要意义.     

压电陶瓷微进给工作台的设计及其实验研究

本文论述了一台由电致伸缩陶瓷制动器驱动的微进给工作以的研制过程,设计了工作台的主体结构,预紧力机构及密封装置,并利用高等材料力学和有限元法优化了主要变形元件,通过ＨＰ５５２８Ａ激光测距系统对其特性进行了测试,工作台最大行程１６μｍ位移分辨率小于０．１μｍ重复定位精度０．１μｍ。     

二维解耦微位移工作台的设计与有限元分析

微位移工作台在微机电系统、超精密加工和生物医学工程等领域有广泛的应用。设计了一种驱动器浮动的二维解耦微位移工作台。工作台采用双层柔性铰链杆对称一体化结构,消除了X、Y方向的耦合运动。推导了微位移工作台的理论刚度。为了验证此微位移工作台能够满足设计要求,采用有限元方法进行分析计算,有限元计算得到的微位移工作台刚度与微位移工作台的理论刚度吻合较好,并且通过有限元计算的结果验证了工作台在X、Y方向的运动无耦合。     

一种激光切割机升降工作台设计

设计了一种激光切割机的升降工作台,对其结构特点、工作原理以及技术要点进行了详细说明,并运用ADAMS软件进行了运动学仿真,为进一步的研究和产品化提供参考依据。     

三自由度微定位工作台的设计与特性分析

设计一种用于平面磨削主动控制的新型数控微定位工作台。该工作台采用三个安装在底座上的压电陶瓷 (PZT)驱动器驱动动平台 ,三个圆形凹槽弹性铰链构成的弹性环节实现对压电陶瓷驱动器的预紧。为了提高定位精度采用三个高精度的电容式位移传感器用来测量动平台的输出 ,从而形成闭环控制系统。采用有限元分析软件ANSYS对微定位工作台的静、动态特性进行了数值分析。     

一种纳米级二维微定位工作台的设计与分析

研究开发了一种采用柔性铰链导向的二维光学调整微定位工作台,建立了工作台的简化模型,并利用结构力学理论推导出工作台沿x、y方向刚度及前二阶固有频率解析式。进行了微定位工作台固有频率及沿x、y方向刚度的试验测试,并结合解析方法和有限元方法对微定位工作台设计刚度及动力特性进行分析验证。有限元分析表明:当工作台的直角平板柔性铰链长度较小而铰链宽度较大时,其刚度、频率及驱动力较高,铰链根部应力集中也较严重。通过改变柔性铰链的特征参数,可达到控制和优化工作台固有频率、输出位移、应力分布及驱动力响应的目的,并提出了一种优选微定位工作台柔性铰链参数的简易方法。     

一种简易铣削回转工作台设计

水泥行业使用的大直径非标烟气阀门,口径尺寸较大（最大口径达到6000mm左右）,其联接法兰、阀体、阀板等圆盘类零件的内外圆要求精加工,加工精度要求不高,达到自由公差就能满足产品要求。文中在不添置大型立式车床或龙门铣等加工设备的情况下,自行设计并制造了一种大型立式铣削回转工作台,在其旁边安装一台动力铣削头,就能够满足非标烟气阀门零部件的加工要求。     

Plasmon-coupled tip-enhanced near-field optical microscopy

Near the cut‐off radius of a guided waveguide mode of a metal‐coated glass fibre tip it is possible to couple radiation to surface plasmons propagating on the outside surface of the metal coating. These surface plasmons converge toward the apex of the tip and interfere constructively for particular polarization states of the initial waveguide mode. Calculations show that a radially polarized waveguide mode can create a strong field enhancement localized at the apex of the tip. The highly localized enhanced field forms a nanoscale optical near‐field source.     

State-selective optical near-field resonant ionization spectroscopy of atoms near a dielectric surface

Spin-sensitive optical near-field microscopy and spectroscopy are proposed based on the study on the conserved quantities in optical near-field interactions of atoms with dielectric surfaces. A two-step photoionization spectra of Cs atoms resolving hyperfine structures are demonstrated near a planar dielectric surface by using evanescent waves. These techniques of state/spin-selective excitation and highly sensitive detection, combined with the techniques of optical pumping, will open up possibilities of space- and polarization-sensitive detection of optical near‐fields using atomic probes. This novel method provides us with a useful technique for the observation of polarization nature of the optical near-field and controlling the spin states of mesoscopic electronic systems.     

Optical-fibre scanning near-field optical microscope for cryogenic operation

We have developed a new type of scanning near-field optical microscope (SNOM) utilizing optical fibres. The probe tip is controlled by shear force feedback with a fibre interferometer and signal light is collected directly by a multimode fibre. These features make the SNOM head more compact and less sensitive to vibration. Further advantages of this new type of SNOM are that it obviates the need for optical windows in the cryostat and offers easy optical alignment.     

Femtosecond near-field scanning optical microscopy study of molecular thin films

A near-field scanning optical microscope has been combined with a two-colour time-resolved pump-probe measurement system. It has a noise-equivalent transmittance change of 5.0 × 10⁻⁵ for a probe pulse with an intensity of 30 nW. The system has been used for evaluating molecular thin films that have a domain structure, particularly for observing a gate action of the single domains. The results include key features to understand an origin of the domains and suggest that the film composition is uniform over a distance of several micrometres.     

Current-sensing scanning near-field optical microscopy using a metal probe for nanometre-scale observation of electrochromic films

A novel technique for scanning near‐field optical microscopy capable of point‐contact current‐sensing was developed in order to investigate the nanometre‐scale optical and electrical properties of electrochromic materials. An apertureless bent‐metal probe was fabricated in order to detect optical and current signals at a local point on the electrochromic films. The near‐field optical properties could be observed using the local field enhancement effect generated at the edge of the metal probe under p‐polarized laser illumination. With regard to electrical properties, current signal could be detected with the metal probe connected to a high‐sensitive current amplifier. Using the current‐sensing scanning near‐field optical microscopy, the surface topography, optical and current images of coloured WO₃ thin films were observed simultaneously. Furthermore, nanometre‐scale electrochromic modification of local bleaching could be performed using the current‐sensing scanning near‐field optical microscopy. The current‐sensing scanning near‐field optical microscopy has potential use in various fields of nanometre‐scale optoelectronics.     

Moulded photoplastic probes for near-field optical applications

The inexpensive fabrication of high-quality probes for near-field optical applications is still unsolved although several methods for integrated fabrication have been proposed in the past. A further drawback is the intensity loss of the transmitted light in the 'cut-off' region near the aperture in tapered optical fibres typically used as near-field probes. As a remedy for these limitations we suggest here a new wafer-scale semibatch microfabrication process for transparent photoplastic probes. The process starts with the fabrication of a pyramidal mould in silicon by using the anisotropic etchant potassium hydroxide. This results in an inverted pyramid limited by < 111 > silicon crystal planes having an angle of ∼ 54°. The surface including the mould is covered by a ∼ 1.5 nm thick organic monolayer of dodecyltrichlorosilane (DTS) and a 100-nm thick evaporated aluminium film. Two layers of photoplastic material are then spin-coated (thereby conformal filling the mould) and structured by lithography to form a cup for the optical fibre microassembly. The photoplastic probes are finally lifted off mechanically from the mould with the aluminium coating. Focused ion beam milling has been used to subsequently form apertures with diameters in the order of 80 nm. The advantage of our method is that the light to the aperture area can be directly coupled into the probe by using existing fibre-based NSOM set-ups, without the need for far-field alignment, which is typically necessary for cantilevered probes. We have evidence that the aluminium layer is considerably smoother compared to the 'grainy' layers typically evaporated on free-standing probes. The optical throughput efficiency was measured to be about 10⁻⁴. This new NSOM probe was directly bonded to a tuning fork sensor for the shear force control and the topography of a polymer sample was successfully obtained.     

Fluorescence imaging with a laser trapping scanning near-field optical microscope

We investigated fluorescence imaging using a near-field scanning optical microscope which uses a laser-stabilized gold nanoparticle as a near-field probe. This microscope is suitable for observations of biological specimens in aqueous solutions because the probe particle is held by a noncontact force exerted by a laser beam. Theoretical calculations based on Mie scattering theory are presented to evaluate the near-field enhancement by a gold particle of 40 nm diameter. We also present fluorescence images of a single fluorescent bead and discuss the near-field contribution to the fluorescence image in this type of microscope.     

Probe design optimization for a high-resolution scattering-type scanning near-field optical microscope

The scattering-type scanning near-field optical microscope (SNOM) has a probe with a sharp tip for use in high resolution imaging. As sharp a tip as possible is generally considered ideal for the observations, but actually, a sharp tip does not always provide a high resolution SNOM image. We numerically examined the scattering property of the SNOM probe by the three dimensional finite difference time domain method. In this paper, we show the criterion for the ideal scattering probe which satisfies the simple relation between radius and taper angle of the tip.     

Photoluminescence imaging of phosphor particles using near-field optical microscope with UV light excitation

We have developed fibre probes suitable for 325 nm UV light excitation and a photoluminescence near-field scanning optical microscope (NSOM) and demonstrated the photoluminescence imaging of phosphor BaMgAl₁₀O₁₇:Eu²⁺ (BAM) particles. The probe was fabricated by a two-step-etching method that we developed. The probe had a large taper angle at the top of the probe and a small taper angle at the root. The NSOM image was different from the topographical structure but roughly reflected the corresponding features of the particles. The inhomogeneity of the photoluminescence intensity between BAM particles was observed in the NSOM image. The photoluminescence intensity with various bandpass filters showed differences between the individual particles, which means that they have different spectra.     

Nano-slit probes for near-field optical microscopy fabricated by focused ion beams

The near-field probes described in this paper are based on metallized non-contact atomic force microscope cantilevers made of silicon. For application in high-resolution near-field optical/infrared microscopy, we use aperture probes with the aperture being fabricated by focused ion beams. This technique allows us to create apertures of sub-wavelength dimensions with different geometries. In this paper we present the use of slit-shaped apertures which show a polarization-dependent transmission efficiency and a lateral resolution of < 100 nm at a wavelength of 1064 nm. As a test sample to characterize the near-field probes we investigated gold/palladium structures, deposited on an ultrathin chromium sublayer on a silicon wafer, in constant-height mode.