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Near-field Optical Microscopy (near-field + optical_microscopy)
Kinds of Near-field Optical Microscopy Selected AbstractsSpontaneous Emission Control in Micropillar Cavities Containing a Fluorescent Molecular Dye,ADVANCED MATERIALS, Issue 6 2006M. Adawi The fabrication of micropillar microcavities containing a fluorescent organic dye is reported. Scanning near-field optical microscopy of the luminescence from such structures (see figure and cover) confirms that a significant increase in radiative rate occurs as a result of the reduced optical-mode volume. Such structures may eventually permit efficient single-photon light sources operating at room temperature to be developed for quantum-cryptography and quantum-computing applications. [source] Upconversion fluorescence imaging of erbium-doped fluoride glass particles by apertureless SNOMJOURNAL OF MICROSCOPY, Issue 3 2003A. Fragola Abstract We have imaged fluorescent erbium-doped fluoride glass particles by apertureless scanning near-field optical microscopy. The optical excitation has been performed at , = 780 nm whereas fluorescence emission has been collected around , = 550 nm. This process, called upconversion by energy transfer, involves two erbium ions and is not linear. Besides an improvement of the lateral resolution, we have observed on some particles that the fluorescence is not homogeneously distributed, but is rather localized in some zones brighter than others. By making tip approach curves, we have also observed that the amount of fluorescence intensity scattered by the tip is increasing when the tip is approaching the sample surface. [source] Current-sensing scanning near-field optical microscopy using a metal probe for nanometre-scale observation of electrochromic filmsJOURNAL OF MICROSCOPY, Issue 3 2003F. Iwata Summary 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. [source] Photo-initiated energy transfer in nanostructured complexes observed by near-field optical microscopyJOURNAL OF MICROSCOPY, Issue 3 2003G. A. Wurtz Summary We report an apertureless near-field optical study on nanostructured objects formed by J-aggregates adsorbed on silver (Ag) nanoparticles. Near-field images reveal that the enhanced near-field from the dressed particle's (DP) resonantly excited plasmon oscillation is efficiently absorbed by the J-aggregates. The sensitivity of the near-field images recorded at the harmonics of the probe vibration frequency suggests that the DP is releasing part of the absorbed energy radiatively upon interaction with the probe. The role of the probe in providing this new radiative relaxation channel is further confirmed as fluorescence from the J-aggregates on the particle is detected on the particle location only. We based the interpretation of our results on the near-field optical response from a bare Ag particle excited at the plasmon resonance as well as on far-field emission and transient absorption experiments. [source] Near-field mapping of surface refractive-index distributionsLASER PHYSICS LETTERS, Issue 9 2005I.P. Radko Abstract Scanning near-field optical microscopy (SNOM) in reflection is employed for high-resolution mapping of surface refractive-index distributions. Two different single-mode optical fibers with step-index profiles are characterized using a reflection SNOM setup, in which cross-polarized detection is employed to increase the contrast in optical images and, thereby, the method sensitivity. The SNOM images exhibit a clear ring-shaped structure associated with the fiber step-index profile, indicating that surface refractive-index variations being smaller than 10,2 can be detected. It is found that the quantitative interpretation of SNOM images requires accurate characterization of a fiber tip used, because the detected optical signal is a result of interference between the optical fields reflected by the sample surface and by the fiber tip itself. The possibilities and limitations of this experimental technique are discussed. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] AFM and SNOM characterization of ordinary chondrites: A contribution to solving the problem of asteroid reddeningPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2010Giuliano Pompeo Abstract Space weathering (SW) is an ensemble of processes that act on a body exposed to the space environment. Typically, the exposure to SW results in the accumulation, at the surface, of nanoparticles, that are thought to be produced through a vaporization and subsequent cooling of the metallo-silicaceous components exposed to the space environment. The presence of such nanoparticles is responsible for the so-called reddening of the asteroids' reflectance spectra (i.e., the increase in Vis,NIR reflectance with increase in wavelength) observed by remote-sensing measurements. To investigate the mechanism of formation of these nanoparticles, we have employed atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) to morphologically and optically characterize ordinary chondrites (OC), the most abundant class of meteorites collected on Earth and whose parent bodies are the S-type asteroids. The AFM study reveals the occurrence of a diffuse nanophase (martensite) in the meteorite's metal inclusions. Since the same areas show a reddening of the reflectivity spectra, this suggests that such spectral modification is based on a shock-induced phase transformation of the metal components of the extraterrestrial body. To gain more insight into this nanophase and on its role in the SW of the asteroids, an optical characterization by SNOM has been performed on OCs. In this work we exploited the peculiarity of this technique to search for a correlation between the topography on the nanoscale and the spectral characteristics, at different wavelengths in the red-NIR range, of the observed nanophase. Indeed, a high-resolution mapping of the optical properties of the meteorite provides an interesting method to discriminate between martensite-based and Fe-silicaceous nanoparticles. [source] Plasmonic nanostructures in aperture-less scanning near-field optical microscopy (aSNOM)PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2008Ralf Vogelgesang Abstract Apertureless scanning near-field optical microscopy offers superb spatial resolution, but interpreting the recorded signal can still be a challenge. Especially images of eigenmodes in plasmonic nanostructures are very often obscured by concurrent scattering from the tip and/or coupling effects in the tip-sample system. We show here how the use of orthogonal polarizations in excitation and detection affords us with an elegant method to map near-fields of plasmonic eigenmodes and other optical phenomena. We demonstrate with a variety of samples possible applications of this cross-polarization scheme, such as verification of functional nanooptical structures, systematic studies of localized and propagating plasmonic eigenmodes, and their susceptibility to disturbance from structural defects. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||