传统光学显微镜与近场光学显微镜

近场光学显微镜是对于常规光学显微镜的革命。它不用光学透镜成像 ,而用探针的针尖在样品表面上方扫描获得样品表面的信息。分析了传统光学显微镜与近场光学显微镜成像原理的物理本质和两种显微镜系统结构的异同点。介绍了光纤探针的制作方法。重点讨论了近场探测原理、光学隧道效应及非辐射场的性质     

近场光学显微镜

近场光学显微镜根据非辐射场的探测与成像原理,能够突破普通光学显微镜所受到的衍射极限,在超高光学分辨率下进行纳米尺度光学成像与纳米尺度光谱研究,本文简介近场光学的基本原理与近场光学显微镜的仪器发展;讨论近年来近扬光学显微镜的一些进展,接近原子分辨的超高分辨率光学成像,近场光谱与半导体量子器件,生命科学中超显微观察和近场荧光以及近场原理在产业化中的应用。     

扫描近场光学显微镜

本文简介近场光学的基本原理一非辐射场的探测与高分辨率的关系；近场光学显微镜的仪器发展。同时简要介绍近场光学显微镜在超高分辨率光学成象，纳米尺度光学微加工与光刻，高密度磁光存储，近场光谱等领域中的应用。     

扫描近场光学显微镜对细胞超微结构的研究

扫描近场光学显微镜(SNOM)突破了光学显微镜的衍射极限,在细胞研究中具有高灵敏性、无侵入性等优点,已经广泛的应用于生物学研究中。本文综述了SNOM在细胞膜、细胞器、细胞精细结构和单分子探测等领域的研究进展,介绍了扫描近场光学显微镜结合量子点的方法,并对其应用前景做了展望,对其面临困难做了概述。作为一种研究工具,SNOM在生物领域的应用还远远不足。     

散射型近场扫描光学显微镜的探针振动参数优化研究

基于原子力显微镜平台设计了可见-近红外波段的散射型近场扫描光学显微镜,通过理论模型计算和实验测量,分析了散射探针振动的调制振幅和扫描反馈幅值对近场信号的影响。研究表明:与探针针尖尺寸相近的调制振幅有利于抑制背景散射噪声及优化近场信号的信噪比;当探针扫描反馈幅值与自由空间调制振幅之比大于90%时,可基本消除探针扫描过程中非简谐振动对近场成像测量的影响。     

原子力与扫描隧道组合显微镜

由大连理工大学物理系研制的原子力与扫描隧道组合显微镜 ( AF/ PSTM) ,9月 2 3日通过了国家教育部组织的鉴定。鉴定委员会对该成果给予了高度评价。该仪器是同时具有纳米分辨原子力显微镜和纳米分辨光学显微镜双重功能图像分解的纳米成像仪器。仪器技术原理是在 AF/ PSTM中设置一个双功能共振光纤尖 ,当光纤尖在样品表面近场扫描时 ,反馈控制等振幅扫描成像 ,一次扫描中 ,同时采集样品的原子力显微镜 AFM图像和光子扫描隧道显微镜PSTM图像。该仪器在分子生物学、医药学、新材料学、集成光学、纳米科技等领域均很有用 ,高校将来甚至…     

近场扫描光学显微镜和光子扫描隧道显微镜

近场扫描光学显微镜和光子扫描隧道显微镜＊王佳（清华大学精密仪器系北京１０００８４）０引言自从８０年代初扫描隧道显微镜ＳＴＭ发明以来，扫描探针显微术ＳＰＭ已经发展成具有十几种类型的系列技术。其中引人注目的是以近场扫描光学显微镜ＮＳＯＭ和光子扫描隧道显微...     

北美和西欧的显微镜市场

本文简述了世界显微镜市场的竞争形势,定量分析了光学显微镜最大的市场——北美和西欧的市场构成以及原西德、日本在显微镜出口方面所占的地位和市场占有率,介绍了美、英、法、意等对光学显微镜的需求,展望了发展趋势。     

突破衍射极限的成像方法综述

"衍射极限"实际上不是一个真正的障碍,除非处理远场和定位精度。这种衍射障碍并不是坚不可摧的,可以利用一些智能技术来突破光学衍射极限。讨论了四种技术,近场扫描光学显微镜(NSOM)法,受激发射损耗(STED)显微镜法,光激活定位显微镜(PALM)法或随机光学重建显微镜(STORM)法和结构照明显微镜(SIM)法,并且介绍了各自的基本原则与优劣。NSOM利用纳米级探测器检测通过光纤的极小汇聚光斑,从而获得单个像素的分辨率;PALM和STORM利用荧光探针,实现暗场和荧光的转换,从而观察到极小的荧光团;SIM则是利用栅格图案与样品叠加成像来实现。其中,STORM具有相对较高的潜力,能够更为有效地突破衍射极限。     

近场光谱仪与近场光谱学

对于在扫描近场光学显微镜基础上发展起来的近场光谱仪的设计原理、基本结构和具体设计作了较具体的讨论，同时，也简要介绍了近场光谱学。     

The tetrahedral tip as a probe for scanning near-field optical microscopy at 30 nm resolution

The tetrahedral tip is introduced as a new type of a probe for scanning near-field optical microscopy (SNOM). Probe fabrication, its integration into a scheme of an inverted photon scanning tunnelling microscope and imaging at 30 nm resolution are shown. A purely optical signal is used for feedback control of the distance of the scanning tip to the sample, thus avoiding a convolution of the SNOM image with other simultaneous imaging modes such as force microscopy. The advantages of this probe seem to be a very high efficiency and its potential for SNOM at high lateral resolution below 30 nm.     

High-speed scanning by dual feedback control in SNOM/AFM

We have developed a high-speed scanning near-field optical microscope (SNOM)/atomic force microscope (AFM) system including dual feedback controllers. The system includes an additional piezoelectric actuator with fast response in the z direction and a correction circuit to eliminate unnecessary components from the feedback signal. From the measurement of a patterned chromium layer of 2 × 2 μm² checks on a quartz glass plate, we confirmed that our system had more effective feedback control and faster scanning than current SNOM/AFM systems that use only a piezo-tube. The scanning speed of the present system was estimated to be about five times faster than that of current SNOM/AFM 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.     

Resolution enhancing using cantilevered tip-on-aperture silicon probe in scanning near-field optical microscopy

Scanning near-field optical microscopy (SNOM) achieves a resolution beyond the diffraction limit of conventional optical microscopy systems by utilizing subwavelength aperture probe scanning. A problem associated with SNOM is that the light throughput decreases markedly as the aperture diameter decreases. Apertureless scanning near-field optical microscopes obtain a much better resolution by concentrating the light field near the tip apex. However, a far-field illumination by a focused laser beam generates a large background scattering signal. Both disadvantages are overcome using the tip-on-aperture (TOA) approach, as presented in previous works. In this study, a finite difference time domain analysis of the degree of electromagnetic field enhancement is performed to verify the efficiency of TOA probes. For plasmon enhancement, silver is deposited on commercially available cantilevered SNOM tips with 20nm thicknesses. To form the aperture and TOA in the probes, electron beam-induced deposition and focused ion beam machining were applied at the end of the sharpened tip. The results show that cantilevered TOA probes were highly efficient for improvements of the resolution of optical and topological measurement of nanostructures.     

A novel light source for SICM–SNOM of living cells

We have developed a novel light source for use in a scanning near‐field optical microscope (SNOM or NSOM) based on a nanopipette whose distance from the sample surface is controlled using scanning ion conductance microscopy. The light source is based on the general principle of the chemical reaction between a fluorophore in the pipette and ligand in the bath, to produce a highly fluorescent complex that is continually renewed at the pipette tip. In these experiments we used fluo‐3 and calcium, respectively. This complex is then excited with an Ar⁺ laser, focused on the pipette tip, to produce the light source. This method overcomes the transmission problem of more traditional SNOM probes and has been used to acquire simultaneous high‐resolution topographic and optical images of biological samples in physiological buffer. A resolution of ～220 nm topographic and ～190 nm optical was determined through imaging fixed sea‐urchin sperm flagella. Live A6 cells were also imaged, demonstrating the potential of this system for SNOM imaging of living cells.     

Inverse estimation of the tapered probe-sample shear force of scanning near-field optical microscope

In this paper, the conjugate gradient method of minimization with an adjoint equation is successfully applied to solve the inverse problem in estimating the shear force between the tapered probe and sample during the scanning process of scanning near-field optical microscope (SNOM). While knowing the available deflection at the tapered probe tip, the determination of the interaction shear force is regarded as an inverse vibration problem. In the estimating processes, no prior information on the functional form of the unknown quantity is required. The accuracy of the inverse analysis is examined by using the simulated exact and inexact measurements of deflection at the tapered probe tip. Numerical results show that good estimations on the interaction shear force can be obtained for all the test cases considered in this study.     

Penetration pathways of fluorescent dyes in human hair fibres investigated by scanning near-field optical microscopy

Thin cross-sections of human hairs were investigated by scanning near-field optical microscopy (SNOM) and confocal laser scanning microscopy (CLSM) after penetration of a fluorescent dye. The same samples were measured with both techniques to compare the observed structures. The images obtained from the two methods show nearly identical structures representing pathways of the dye molecules in hairs. The SNOM images provide a higher resolution than the CLSM images. Therefore, SNOM is believed to be a suitable method for investigations at a resolution of 100 nm on penetration pathways of fluorescent dyes such as the cell membrane complex pathway in cross-sections of hairs.     

Polarization properties of bent-type optical fibre probe for magneto-optical imaging

Quantitative evaluation of magneto-optical parameters is necessary in order to apply scanning near-field optical microscope (SNOM) technology to the study of magnetism on the mesoscopic scale. For this purpose, quantitative knowledge of polarization transmission properties through an optical fibre probe is required. We therefore determined the Stokes parameters of the bent-type optical fibre probe that is used as a cantilever for atomic force microscope operation in our SNOM system. As a result, it is found that the degree of polarization is maintained in the light emitted from the probe, although the probe acts as if it were a wave plate. This anisotropic polarization state of the light emitted from the probe was compensated for by using a Berek compensator placed in front of the fibre coupler.     

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.