A novel phase-sensitive scanning near-field optical microscope

Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.

Multi-mode Scanning Near-field Optical Microscope

A scanning near-field optical microscope using uncoated fiber tip is described, which can work in transmission and reflection configurations, both capable of working in illumination and collection-mode, so that either transparent or opaque sample can be investigated. Depending on different applications, either constant-gap or constant-height images can be achieved. A compact homemade translator permits to select interested area of sample in the range of 4 mm×4 mm. Working in the constant-height as well as transmission and collection-mode configuration, several kinds of samples such as holographic grating, liposome and zeolite were investigated. The experimental results revealed the dependence of the optical resolution of the SNOM on the tip-sample separation.

Standing-wave spectrometry in silicon nano-waveguides using reflection-based near-field scanning optical microscopy

Utilizing reflection-based near-field scanning optical microscopy(NSOM) to image and analyze standing-wave patterns, we present a characterization technique potentially suitable for complex photonic integrated circuits. By raster scanning along the axis of a straight nano-waveguide in tapping mode and sweeping wavelength, detailed information of propagating waves in that waveguide has been extracted from analyses in both space and wavelength domains. Our technique needs no special steps for phase stabilization, thus allowing long-duration and environment-insensitive measurements. As a proof-of-concept test, in a silicon single-mode waveguide with a few of etched holes, the locations and reflection strengths of the inner defects have been quantified. The measurement uncertainty of the reflection amplitude is less than 25% at current stage. Our technique paves the way for non-destructively diagnosing photonic circuits on a chip with sub-wavelength spatial resolution and detailed information extraction.

Optical polarization response at gold nanosheet edges probed by scanning near-field optical microscopy

Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the near-field optical polar- ization response at the edge of a triangular gold nanosheet, which is synthesized by a wet chemical method. A homemade scanning near-field optical microscope （SNOM） in collection mode is adopted, which is able to accurately locate its probe at the edge during experiments. An uncoated straight fiber probe is used in the SNOM, because it s611 preserves the prop- erty of light polarization though it has the depolarization to some extent. By comparing near-field intensities at the edge and glass substrate, detected in different polarization directions of incident light, the edge-induced depolarization is found, which is supported by the finite differential time domain （FDTD） simulated results. The depolarized phenomenon in the near-field is similar to that in the far-field.

Influence of the probe-sample interaction on scanning near-field optical microscopic images in the far field

We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SNOM image contrast between the two sides of the step changes periodically at different scan heights. For a step height of-λ/2, the image contrast remains approximately the same. The probe-sample interaction determines the SNOM image contrast here. The influence of different refractive indices of the sample has been also analysed by using a simple theoretical model.

Scanning Head for the Apertureless near Field Optical Microscope

The design and characterization of a tip control unit for an apertureless scanning near field optical microscope (ASNOM) is reported. To make the instrument operation easier, the cantilever control parts (piezo excitation of the cantilever vibration for the dynamic mode feedback and the parts necessary for the optical lever scheme of the vibration control) were placed in a separate detachable assembly. To suppress the influence of vibrations of the setup, the assembly was made lightweight. Good optical access to the ASNOM tip from various directions is provided in the system. High long-term mechanical stability of the system (~50 nm lateral drift in 18 hours) as well as low sensitivity to seismic vibrations (~400 pm RMS) is demonstrated. It is shown that external sound is not a main source of noise in the topography image (~200 pm RMS). The light field distribution (with its amplitude and phase) around the ASNOM tip was acquired by scanning the focal spot around the tip, and a high optical quality of the system is demonstrated.

Micro-Scanning Error Correction Technique for an Optical Micro-Scanning Thermal Microscope Imaging System

An error correction technique for the micro-scanning instrument of the optical micro-scanning thermal microscope imaging system is proposed. The technique is based on micro-scanning technology combined with the proposed second-order oversampling reconstruction algorithm and local gradient image reconstruction algorithm. In this paper, we describe the local gradient image reconstruction model, the error correction technique, down-sampling model and the error correction principle. In this paper, we use a Lena original image and four low-resolution images obtained from the standard half-pixel displacement to simulate and verify the effectiveness of the proposed technique. In order to verify the effectiveness of the proposed technique, two groups of low-resolution thermal microscope images are collected by the actual thermal microscope imaging system for experimental study. Simulations and experiments show that the proposed technique can reduce the optical micro-scanning errors, improve the imaging effect of the system and improve the system's spatial resolution. It can be applied to other electro-optical imaging systems to improve their resolution.

Analysis of Near-Field Diffraction Pattern of a Metallic Probe Tip with the Boundary Diffraction Wave Method

The boundary diffraction wave theory is introduced to analyse a near-field diffraction （NFD） pattern of a metallic probe tip of apertureless scanning near-field microscopy. This method is simple and can give a clear physical picture. The polarization effect of the incident light and the different shapes of the metallic probe tip are simulated. The results show that the NFD pattern of the metallic probe tip is directly related to those factors.

多束电子光学系统的研究现状与发展

本文对多束电子光学系统的国内外研究现状进行了详细调研,总结了各个系统的特点以及应用领域。多束电子光学系统在生命科学领域、材料领域以及半导体领域具有广泛的应用价值,本文指出了我国需要开展这方面研究的必要性。同时,本文介绍了国内在多束电子光学领域的研究进展。

光学显微镜观察法与扫描电子显微镜观察法的分析与比较

对于纸张来说,时常需要对纸张中的纤维、填料以及一些纸病进行观察分析。目前实验室中常用的观察、分析类仪器有光学显微镜以及扫描电子显微镜。本文就纸张的光学显微镜观察法与扫描电子显微镜观察法进行初步分析比较。

光学麦克风封装材料相容性试验

为确保光学麦克风在电气设备内部应用的安全可靠性,文中选定聚氨酯、聚四氟乙烯、环氧树脂、聚醚醚酮和酚醛树脂作为封装材料,进行光学麦克风与电气设备相关的环境相容性试验,并采用扫描电子显微镜(scanning electron microscope,SEM)和傅里叶变换红外(Fourier transform infrared,FTIR)光谱仪对试验前后的材料性能进行检测。结果表明:聚氨酯表面易浸润变压器油且有明显颜色变化,不适用于油浸式变压器,但可用于水听器、空气和常温环境中;聚四氟乙烯与变压器油的相容性较好,可用于油浸式变压器、气体绝缘开关设备(gas insulated switchgear,GIS)和温度变化较大的场景;其余材料与电气设备的相容性不佳,适用性有待进一步研究。文中提出的封装材料与环境相容性试验的检测方法可为光学麦克风封装材料选型提供有益借鉴,具有一定的工程实用价值。

Polarization-insensitive plasmon nanofocusing with broadband interference modulation for optical nanoimaging

Delivering light to the nanoscale using a flexible and easily integrated fiber platform holds potential in various fields of quantum science and bioscience.However,rigorous optical alignment,sophisticated fabrication process,and low spatial resolution of the fiber-based nanoconcentrators limit the practical applications.Here,a broadband azimuthal plasmon interference nanofocusing technique on a fiber-coupled spiral tip is demonstrated for fiber-based near-field optical nanoimaging.The spiral plasmonic fiber tip fabricated through a robust and reproducible process can reverse the polarization and modulate the mode field of the surface plasmon polaritons in three-dimensionally azimuthal direction,resulting in polarization-insensitive,broad-bandwidth,and azimuthal interference nanofocusing.By integrating this with a basic scanning near-field optical microscopy,a high optical resolution of 31 nm and beyond is realized.The high performance and the easy incorporation with various existing measurement platforms offered by this fiber-based nanofocusing technique have great potential in near-field optics,tip-enhanced Raman spectroscopy,nonlinear spectroscopy,and quantum sensing.

Development and prospect of near-field optical measurements and characterizations

Scanning near-field optical microscopy （SNOM） is an ideal experimental measuring system in nano-optical measurements and characterizations. Besides microscopy with resolution beyond the diffraction limit, spectroscope with nanometer resolution and other instruments with novel performances have been indispensable for researches in nano-optics and nanophotonics. This paper reviews the developing history of near-field optical （NFO） measuring method and foresees its prospects in future. The development of NFO measurements has gone through four stages, including optical imaging with super resolution, near-field spectroscopy, measurements ofnanooptical parameters, and detections of near-field interac- tions. For every stage, research objectives, technological properties and application fields are discussed.

过焦扫描光学显微测量技术综述

随着半导体产业的发展和器件性能的不断提升,半导体器件的特征尺寸越来越小,器件结构越来越复杂,对检测仪器的性能提出了更高的要求。首先介绍过焦扫描光学显微法(Through-focus Scanning Optical Microscope,TSOM)的测量装置及测量原理,该方法可实现三维几何参数的无损测量,因其具有精度高、速度快、成本低等优点,可以满足在线测量的需求;然后从TSOM图构建和待测参数提取两个方面对TSOM方法的研究进展进行了梳理和归纳;最后对TSOM方法未来的研究重点和发展方向进行了展望。该方法有望为我国半导体制造产业提供新的检测手段,为优化和提升我国半导体制造工艺提供重要的技术支撑。

激光共聚焦显微镜与光学显微镜之比较

激光扫描共聚焦显微镜在活细胞的动态检测、光学切片和三维结构重建等方面较光学显微镜有质的飞跃。本文对激光扫描共聚焦显微镜和光学显微镜进行了比较和讨论 ,并简单介绍多光子激光扫描显微镜。

影响黄土湿陷性因素的微观试验研究

借助扫描电子显微镜和光学数码显微镜,分析了不同含水率黄土试样表面微区结构变化与黄土湿陷性的关系和不同埋深土样在水与外力共同作用下湿陷前后微观结构的变化特征。利用图像处理软件对所获取的微结构图像进行研究,分析了黄土湿陷前后土样中大、中、小孔隙和微孔隙数量的变化。结果表明:湿陷后比湿陷前土样微孔隙增多31.18%,小孔隙增多54.07%,中孔隙减少30.49%,大孔隙减少90.14%。这说明随着压力的不断增大,黄土中的孔隙被逐渐压缩,大孔隙和中孔隙的数量逐渐减少,小孔隙和微孔隙的数量逐渐增加,为黄土的湿陷变形提供了充分的空间。讨论了土样中4类孔隙对黄土湿陷的贡献量,从微观角度综合分析了黄土湿陷的成因机理。

中华须鳗嗅觉器官形态学观察

利用光学显微镜和扫描电镜观察了10尾不同体长中华须鳗嗅觉器官的结构。结果表明:中华须鳗嗅囊呈楔型;嗅囊膜和嗅囊腹面的透明膜共同围成嗅囊腔;嗅囊长径与眼径的平均比值为2.2倍;每侧嗅囊嗅板数变化范围在30～44之间;嗅板远轴端有一纤毛和嗅孔密集的舌状游离突;嗅板上皮纤毛密集,纤毛细胞表现为3种类型:纤毛感觉细胞、纤毛非感觉细胞和微绒毛感觉细胞;纤毛非感觉细胞和微绒毛细胞也出现在嗅囊壁。嗅板上大量的纤毛表明,中华须鳗嗅囊的水动力机制应属嗅板纤毛搅动型(isosmates)。除观察到嗅囊壁表面有两种类型的微嵴外,还首次在嗅板上观察到一种呈荸荠状的杆状细胞。

扫描探针显微术的应用(综述)

扫描探针显微镜 (SPM)是扫描隧道显微镜 (STM)、原子力显微镜 (AFM)、近场光学显微镜(SNOM)等近几年发展起来的新型显微镜的总称 .SPM的发展使得在纳米尺度上研究物质的特性和相互作用成为可能 ,它为生物。

武广高速铁路风化花岗岩微观变化特征研究

结合工程实例,研究了风化过程中花岗岩的微观变化特征,采用光学显微镜、扫描电镜等测试手段,以风化剖面上的钻孔岩心为样本来源,揭示了花岗岩从弱风化演变为强风化过程中,微结构由粒状堆砌微结构演变为粒状架空微结构,粒间联结力由紧密演变为疏松,微裂隙由不发育演变为很发育,蚀变产物增多,粘土矿物大量增加,表明风化作用正是通过在改变了岩石的矿物成分、化学成分的基础上改变了岩石的微观结构特征,才最终改变了岩石的宏观力学性能。

激光扫描共聚焦显微镜

阐述了激光扫描共聚焦显微镜(LSCM)的原理和构造,分析了LSCM的优点和缺点,如获得清晰的图像,可光学切片、三维重建,实时多通道荧光,ZOOM放大,局部光操作,检测过程快、效果更灵敏、定位更准确。探讨了LSCM扫描方式及应用,如研究多种荧光定位分析,需选择XY扫描;研究标本空间实际位置信息,样品三维图像信息,需选择XYZ扫描;用于研究活体标本随时间的变化,或在不同时间采取不同的处理方法观察标本的荧光变化研究,得选择XYT扫描。并针对目前管理该仪器设备上存在的问题提出一些建议,以期对高校实验室的开放共享提供有益参考。