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A wide variety of near-field optical phenomena are described by the interaction of dipole radiation with a nanophotonic system. The electromagnetic field due to the dipole excitation is associated with the Green’s function. It is of great interest to investigate the dipole interaction with a photonic system and measure the near-field Green’s function and the quantities it describes, e.g., the local and cross density of optical states. However, measuring the near-field Green’s function requires a point-source excitation and simultaneous near-field detection below the diffraction limit. Conventional single-tip near-field optical microscope (SNOM) provides either a point source excitation or amplitude and phase detection with subwavelength spatial resolution. The automated dual-tip SNOM, composed of two tips, has overcome the experimental challenges for simultaneous near-field excitation and detection. Here, we investigate the dipole emission in the near-field of a dielectric metasurface using the automated dual-tip SNOM. We have analyzed the near-field pattern and directional mode propagation depending on the position of the dipole emission relative to the metasurface. This study is one further step toward measuring the dyadic Green’s function and related quantities such as cross density of optical states in complex nanophotonic systems for both visible and near-infrared spectra.

This work reports the first images obtained by combining an infrared aperture scanning near-field optical microscope (SNOM) with a quantum cascade laser (QCL). The future potential of this set-up is demonstrated by a preliminary study on an OE33 human oesophageal adenocarcinoma cell in which the cell is imaged at 1751 cm-1, 1651 cm-1, 1539 cm-1 and 1242 cm-1. In addition to the 1651 cm-1 image, three other images were acquired within the Amide I band (1689 cm-1, 1675 cm-1 and 1626 cm-1) chosen to correspond to secondary structures of proteins. The four images obtained within the Amide I band show distinct differences demonstrating the potential of this approach to reveal subtle changes in the chemical composition of a cell.

A hybrid conventional inverted/scanning near-field optical microscope (Inverted/SNOM) has been obtained, by coupling an Olympus IX-70 optical microscope with a SNOM head to combine the versatility and ease of use of the conventional microscope with the high-resolution and three-dimensional reconstruction obtainable with the SNOM technique. The head can be run in shear or tapping mode and is optimized to characterize soft, biological samples including living cells in physiological environment by including the SNOM in a cylindrical chamber that insulates it from the external noise, while maintaining a controlled temperature and atmosphere. Applications in the fields of biology and material science are presented.

In addition to its well-known capabilities in imaging and spectroscopy, scanning near-field optical microscopy (SNOM) has recently shown its great potentials for fabricating various structures at the nanoscale. A variety of SNOM-based fabrication techniques have been developed for different applications. In this paper, the SNOM-based techniques involving three major functions: material modification, addition, and removal, are examined with emphasis on their abilities and reliability to make structures with resolutions at the nanometer level. The principles and procedures underlying each technique are presented, and the differences and uniqueness among them are subsequently discussed. Finally, concluding remarks are provided to summarize the major techniques studied and to recommend the scopes for technology improvement and future research.

We demonstrate the fluorescence mapping of protein microarrays by the technique of scanning near-field optical microscopy (SNOM) and confocal microscopy. Micron sized spots (300 μm) of human Immunoglobulin G (hIgG) protein with and without a Cy3 dye labeling have been fabricated on glass substrates by an immobilization method which makes use of calixcrown derivatives termed Prolinker. We have also tried to probe into the well-known “doughnut effect” observed in fluorescence images of proteins using the SNOM technique. The topographic and fluorescence SNOM images revealed that the number of proteins at the boundary of the spot were more than at the center in the case of the microarray spot which showed brighter luminescence at the edge than at the center in the confocal image.

A new scanning near field optical microscope operating in the intermittent contact mode (Tapping SNOM) using a non-bent optical fiber is presented. The main advantages in terms of versatility and quality of the collected signal are described together with some results obtained studying fluorescence on material science samples and spectroscopy images of living cells.

The local near-field light scattering and the series dynamic progress of dyestuff PAN particles in solution were investigated taking advantage of optical fiber probe and the near-field detection techniques, including the dissolving and crystallizing progress, Brownian movement and the statistical distribution of particles. Some useful and interesting results were obtained, and are in good agreement with the theoretical analysis. These findings will contribute to the research of near-field optics in a liquid environment as well as provide direct and valuable results for statistical physics.

Deformation of an organic photosensitive azopolymer by near-field light generated by an optical fiber probe with a very small aperture diameter of about 50 nm is studied. The azopolymer is deformed in response to the polarization state of the light incident on the probe. If the probe aperture diameter is made smaller, the mark shape can be made smaller but the probe must be moved closer to the material. However, the mark width is about 6 times the probe aperture diameter. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(3): 55–61, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10129

To investigate basic processes responsible for brain functions by nano-imaging, we have developed a near-field optical microscope and successfully visualized fine structures and snapshot of the states of astrocytes and neurons.

We report a novel method for the fabrication of probes with localized sub-wavelength fluorescing media at their extremities. We present our first results and discuss future plans to extend this technique to the systematic fabrication of fluorescent probes for apertureless scanning near-field optical microscopy.

We study a nanometer-sized optical probe and image in a scanning near-field optical microscope (SNOM). We demonstrated the potential to observe 5-nm wide optical patterns using the SNOM. The probe profile was measured by using a knife-edge method and a modulated transfer function evaluation method. An aluminum covered and pipet-pulled fiber probe used here has two optical probes, one which has a large diameter of 350 nm and one which has a small diameter of around 10 nm.

solution and a sample which is electrically conductive and transparent in the visible region (ITO coated glass). We also present some details such as shear force distance control in liquids and light guiding in pulled and filled micropipettes. Macroscopic experiments demonstrate localized deposition and allow to estimate parameters for microscopic deposition. Diameters of first deposited dots are smaller than 1 μm.

キセノンランプからの白色光を光源とし,光走査トンネル顕微鏡方式の走査型近接場光学顕微鏡(SNOM)を試作した.微小領域の透過スペクトルを得るための基礎実験として,銅フタロシアニン及び金の2種類の薄膜試料に関して透過スペクトルを得ることを試みた.SNOMで得られた透過スペクトルを市販の分光光度計による測定結果と比較したところ,銅フタロシアニンの薄膜に対しては両者のスペクトルは良く一致したが,金の薄膜の測定結果はSNOMと分光光度計とで反対の傾向を示した.両者の測定結果の違いを金の薄膜に励起される表面プラズモンによって説明した.

We present an analysis of the properties of an imaging based on a near-field recording technique in comparison with simulation results. In the system, the optical field distributions localized near the specimens are recorded as the surface topographic distributions of a photosensitive film. It is possible to observe both soft and moving specimens, because the system does not require a scanning probe to obtain the observed image. The imaging properties are evaluated using fine structures of paramecium, and we demonstrate that it is possible to observe minute differences of refractive indices.

Within the framework of a microscopic formalism, we present a theoretical analysis of the imaging properties of scanning near-field optical microscopy in reflection. The detected optical signal is assumed to be proportional to the intensity of the self-consistent field at the site of the probe dipole. Influence of different components (near, middle and far fields) of the field propagator on the total field intensity is numerically studied for two arrangements of object dipoles and for various probe-surface distances. We demonstrate that for relatively large distances the middle-field components dominate in the total field and ensure the subwavelength resolution. Imaging properties of the reflection near-field microscopy observed experimentally are qualitatively explained with the help of our numerical simulations.

Near-field optical recording using magneto-optic, phase-change, and photochromic materials was reviewed. Among them, rewritable recording using photochromic media was described in detail. Marks as small as 100nm in width were recorded on the dithienylethene photochromic media by irradiation with 529-nm light, and erased by irradiation with UV light (300nm < λ < 400nm).

We show that the combination of a scanning near field optical microscope and an infra-red free electron laser yields chemical images with sub-cellular spatial resolution that have the potential to provide a diagnostic for oesophageal adenocarcinoma.

We propose an application of the ISTOM to characterize nano-sources used in Scanning Near-Field Microscopies. The model takes into account the coupling between the nano-source and the hemispherical lens of the ISTOM set-up. By changing the angle of detection, experimental data are related to the Fourier spectrum of the source. We show “images” calculated with two different distances between tip end and lens surface.

A method of optical distance control for an aperture-SNOM has been developed, which is especially useful for investigations at the liquid/air interface. The method is based on modulations in the transmitted light, which appear when the tip is moved toward the sample. This effect is due to interference. By tracking an extremum of the transmitted light intensity, the distance regulation is not affected by local differences in the transmission of the sample. When taking an image, during the backward scan the distance control keeps the distance between tip and sample constant. During the forward scan the feedback is switched off and the tip is further moved toward the sample, to bring it into the near-field region. Since the feedback is not active at all times, the proposed method is suitable only for flat samples. Images of a solid test specimen, obtained by applying optical distance control are presented in this communication.

Scanning near-field optical microscopy (SNOM) was applied to phase-change (PC) mark writing to investigate the potential of ultrahigh density data storage. GeSbTe, one of the typical PC media, was used as a recording layer. Using a laser diode (LD) with a wavelength of 785 nm as light source, crystalline marks with a minimum size of ∼ 80 nm in diameter were successfully written in the amorphous GeSbTe film with pulse conditions of 5 ms and 0.5 ms and 8.4 mW inside the probe. The detected power in observation of the marks was 10 2 –10 3 times as high as that in magneto-optical (MO) observation.

The design of tips is of outstanding importance to obtain maximal efficiency in scanning near-field microscopy. As a support towards this optimization, this work presents the computation of the electromagnetic field penetrating into two-dimensional tips. The investigated geometries consist of elongated two-dimensional dielectric slabs (glass) terminated by pointed tips. Distributions of the electric field amplitude inside and outside two-dimensional models of tips are computed and from those solutions, far-field differential cross-sections are obtained.

The early eighties have experienced a revolution in the perception of physical phenomena. This revolution is the birth of a new generation of imaging systems based on the detection of non-radiating fields. The near field optical microscope is the latest of this family. Like its prestigious brothers, the STM and the AFM, it allows one to see the physical world with new eyes. The objective of this article is to provide an overview concerning the physical mechanisms and paradoxes taking place in non-radiative detection. We will first explain the connection between Heisenberg uncertainty relations and the Rayleigh criterion. The fundamental role of evanescent fields will be pointed out through the plane wave expansion. Finally a catalogue of the different configurations currently in use will be given and illustrated with some experimental results.

Un microscope a effet tunnel (STM) peut etre utilise en meme temps comme un microscope optique en champ proche (SNOM), si la pointe du STM est remplacee par une pointe en fibre optique monomode metallisee avec de l'or, et si l'on ajoute un montage optique pour l'excitation et la detection. Grâce a une meilleure regulation de distance entre la pointe et l'echantillon, et surtout a une tres courte distance de regulation (

Optical observation of the polarization domain structure of a ferroelectric material (triglycine sulfate) is achieved using a reflection apertureless near-field optical microscope operating with an electrical ac polarization of the tip. By showing that there is no detectable contribution of the converse piezoelectric effect of the sample nor of the electrical forces acting on the tip in the optical signal detected, we explain the observed contrast between domains of opposite polarity by the electro-optic effect. Using the phase of the demodulated optical signal, we image the ferroelectric domain structure with a resolution better than 35 nm.

In this paper we present some investigations on the near field based on a novel approach for scattering technique. Our new scanning near field optical microscope is introduced for resolving optical properties of surfaces with lateral resolution reaching 10 nm and better. The different works modes of the system are presented.

This chapter reports a broad overview of near-field optical probes. They represent the key components for the performance of the scanning near field optical microscope (SNOM). In this frame, we consider the two main classes of sensors: aperture and apertureless probes. In particular, attention is focused on optical fiber probes and on nanoantenna probes. Recent developments in the improvement of optical throughput and in the control of the near field polarization state are reported. The electromagnetic field distributions of the nanometric optical source, as well as the fabrication methods are dealt with. In order to provide a clear, complete and comprehensive description of the technique, brief explanations of the working principles of the SNOM and conventional microscopy are given. Finally, this chapter is tale about recent SNOM applications that have been widened thanks to the improved features of the probes.

The cover image shows the surface topography of a phase-separated blend of two conjugated polymers. On p. 107, Lidzey and co-workers show that the fluorescence decay lifetime of a conjugated polymer in such a blend can vary significantly between the different phase-separated domains. This variation results in a marked dependence of the photoluminescence quantum efficiency on the relative blend composition.

A Scanning Near-field Optical Microscope (SNOM) was used to inscribe locally limited Surface Relief Gratings (SRGs) on pDR1M, which is an azo-polymer film. The influence of parameters such as the line scanning time and the line spacing on the amplitude and the period of the gratings is discussed. SRGs have been used to orient Liquid Crystals (LCs), where the LC alignment takes place due to the elastic distortions of the nematic medium close to the surface. In addition, the photoalignment of the azo-chromophores was also used to induce LC alignment. In this work we investigate the use of local SGRs together with the photoalignment to get a local control of the LC alignment properties. The advantage of this method is that it is reversible and the gratings can easily be erased.

This article has done some observation to biological electret fish scale with kinds of detective methods like optical microscope, atom-dint microscope, and near field optical microscope, and discovered that the biological electret fish scale has the ordered permutation and self-similar characteristic.

A new aperture scanning near-field optical microscope operating in the intermittent contact mode using a non-bent optical fiber is introduced. The microscope was built modifying a classical scanning near-field optical microscope (SNOM) unit introducing a patented probe-holder (MTP) which contains a piezo-motor and a bimorph-transductor. The main advantages of the present set-up in terms of stability, versatility, optical resolution, and quality of the collected signals are described. The instrument works properly while exerting a minimum perturbation on the sample thus overcoming the major drawbacks of different SNOM-based imaging modes and allowing to study very delicate samples including living cells in physiological environment.

The mechanical resonance behavior of near-field optical microscope probes is examined with a simple experiment on a flat pyrex sample. While our tapered-fiber probe is locked on the second resonance for servo control, the vibration characteristics around the first resonance are investigated. We find that the overwhelming cause of decreased vibration amplitude as the tip approaches the sample is an increase in damping presumably due to a fluidlike layer on the sample. A small additional effect is also observed that could be due to force derivatives.

A new design of a tunneling near-field optical microscope (TNOM) combined with an atomic force microscope (AFM) is presented. This design can be used to generate three different images of the sample's surface: a non-contact (tapping mode) AFM image, a conventional TNOM and an image of a modulation signal of the conventional TNOM, which we call AC-TNOM. The images are obtained simultaneously, using a single light source. It is shown that the AC-TNOM has better resolution ( approximately 200A) and contrast compared to conventional TNOM ( approximately 400A).

In this paper the Rayleigh-Ritz method was used to study the scanning near-field optical microscope (SNOM) with a tapered optical fiber probe's flexural and axial sensitivity to vibration. Not only the contact stiffness but also the geometric parameters of the probe can influence the flexural and axial sensitivity to vibration. According to the analysis, the lateral and axial contact stiffness had a significant effect on the sensitivity of vibration of the SNOM's probe, each mode had a different level of sensitivity and in the first mode the tapered optical fiber probe was the most acceptive to higher levels of flexural and axial vibration. Generally, when the contact stiffness was lower, the tapered probe was more sensitive to higher levels of both axial and flexural vibration than the uniform probe. However, the situation was reversed when the contact stiffness was larger. Furthermore, the effect that the probe's length and its tapered angle had on the SNOM's probe axial and flexural vibration were significant and these two conditions should be incorporated into the design of new SNOM probes.

We report time-resolved acoustic measurements in the picosecond range performed with a 100 nm lateral resolution. A near field optical microscope operating in reflection geometry and coupled with a standard picosecond acoustic setup is described. Results obtained on thin film are discussed and prove that the sensitivity of our system allows the observation of thermal features and acoustic signals such as echoes and surface waves. Patterned structures made of submicrometric metallic dots have also been studied: it is demonstrated that, owing to the high lateral resolution which we obtained, vibrational modes of a single dot are detected.

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.

In this chapter, we study the basic electromagnetic processes involved in near-field optical microscopes (NOM) from the theoretical viewpoint of the multiple scattering of a vector field. The purpose is to examine the localization of the near-field interaction between small dielectric objects. Such a process is relevant to the near-field detection of near-field phenomena. We will show how we can obtain information about localized electromagnetic interactions between small objects.