Infrared near-field

SOURCE Reprinted with permission from Taubner, T., R. Hillenbrand, and F. Keilmann. 2004. Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy Appl. Phys. Lett. 85 5064-5066. Copyright 2004, American Institute of Physics. 

Emerging new methods include resonant X-ray scattering [109], for enhanced contrast, critical-dimension SAXS, giving access to a 3D reconstruction [110] of in-depth structural features in the films, and scattering infrared near-field microscopy [111], for nanoscale chemical analysis at surfaces. 

A nano-light-source generated on the metallic nano-tip induces a variety of optical phenomena in a nano-volume. Hence, nano-analysis, nano-identification and nanoimaging are achieved by combining the near-field technique with many kinds of spectroscopy. The use of a metallic nano-tip applied to nanoscale spectroscopy, for example, Raman spectroscopy [9], two-photon fluorescence spectroscopy [13] and infrared absorption spectroscopy [14], was reported in 1999. We have incorporated Raman spectroscopy with tip-enhanced near-field microscopy for the direct observation of molecules. In this section, we will give a brief introduction to Raman spectroscopy and demonstrate our experimental nano-Raman spectroscopy and imaging results. Furthermore, we will describe the improvement of spatial resolution... 

D. Vobornik, PhD thesis Scanning near-field Infrared Microscopy and Spectromicroscopy Applied to Nano-systems and Cells. Lausanne, 2005. 

Osawa, M., Surface enhanced infrared absorption, In Near Field Optics and Plasmon Polar itons Kawata, S., Ed. Springer, Berlin, 2001, 163 187... 

Near-field scanning optical microscope (NSOM), 16 501-503 Near-infrared absorbing dyes, 9 341 Near-infrared spectroscopy (nir),... 

Methods of near-field, midfield and ensemble (global) imaging and real-time visualization have been developed for monitoring gas atomization of liquid metals.[327] The primary process sensors and monitors used include high-speed video and infrared imaging systems. The process monitors allowed continuous and detailed observations of the atomization process and enabled measurements of the key parameters necessary for adequate control and optimization of the process. The sensors provided the operators with real-time information on the temperature of nozzle tip, visual characteristics of atomization plume, and gas and metal flow rates. The images can be displayed in real time, offering the potential for more responsive process control. 

The interaction of cesium ions with feldspars at 150°C and 200°C has been studied in distilled water, granite groundwater and saline solution Pollucite, CsAlSi206, was identified by infrared spectroscopy, and was formed as a cubic crystalline phase. Surface analytical techniques (XPS, SAM, SIMS and SEM/ EDX) show Cs to be sorbed onto the mineral surfaces and alteration products. The mechanism of pollucite formation and its relevance to cesium transport/ retardation in the near field of a nuclear waste-disposal vault is discussed. 

Brighter, tunable ultrafast light sources would benefit many of the areas discussed in the report, particularly infrared-terahertz (between visible light and radio waves) vibrational and dynamical imaging, near-field scanning optical microscopy (NSOM), and X-ray imaging. 

FIGURE 3.18 Images showing representative data from phase-separated domains of poly(styrene) in a poly(methyl methacrylate) matrix. Left sample topography. Right apertureless infrared scattering near-field optical images of poly(styrene) domains in a poly(methyl methacrylate) film recorded at the frequencies shown. 

Michaels, C.A., S.J. Stranick, L.J. Richter, and R.R. Cavanagh. 2000. Scanning near-field infrared microscopy and spectroscopy with a broadband laser source. J. Appl. Phys. 88 4832. 

Dragnea, B., J. Preusser, W. Schade, S.R. Leone, and W.D. Hinsberg. 1999. Transmission near-field scanning microscope for infrared chemical imaging. J. Appl. Phys. 86 2795-2799. 

NIH NIR NMR NRS NSOM National Institutes of Health Near Infrared Nuclear Magnetic Resonance Nuclear Resonant Scattering Near-field Scanning Optical Microscopy... 

Fourier-Transform Infrared (FTIR) spectroscopy as well as Raman spectroscopy are well established as methods for structural analysis of compounds in solution or when adsorbed to surfaces or in any other state. Analysis of the spectra provides information of qualitative as well as of quantitative nature. Very recent developments, FTIR imaging spectroscopy as well as Raman mapping spectroscopy, provide important information leading to the development of novel materials. If applied under optical near-field conditions, these new technologies combine lateral resolution down to the size of nanoparticles with the high chemical selectivity of a FTIR or Raman spectrum. These techniques now help us obtain information on molecular order and molecular orientation and conformation [1],... 

Spectromicroscopy — Most optical spectroscopies probe rather large areas or volumes because the beam of light (whether infrared, UV-Vis, or X-ray etc.) probing the electrochemical interface or the electrolyte solution volume in front of the electrode (the interphase) has a finite diameter ranging from several 10 micrometers to a few millimeters or even more. Thus, spatially or locally resolved information cannot be obtained. Employing confocal or near-field optics very small surface areas can be probed, resolutions down to a few micrometers are possible. 

Microscopic visualization techniques have also been used to investigate mucus-polymer interactions. Transmission electron microscopy was used by Fiebrig et al., whereas different microscopical techniques were used by Lehr et al. for the visualization of mucoadhesive interfaces. Transmission electron microscopy in combination with near-field Fourier transform infrared microscopy (FTIR) has been shown to be suitable for investigating the adhesion-promoting effect of polyethyleneglycol added in a hydrogel. Moreover, scanning force microscopy may be a valuable approach to obtain information on mucoadhesion and specific adhesion phenomena. ... 

High enhancement of the copper localized surface plasmon absorbency was recorded at the two-layer planar system consisted of copper and silver nanoparticles prepared with successive vacuum evaporation. The result obtained may be caused by strong near-field coupling in the close-packed binary system. The effect may be used for the development of high-absorptive coatings and spectral selective nanoelements in the visible and near infrared spectral ranges. 

IR measurements on doped Si and shown that the subsurface mobile carriers can be probed by their response to an IR near-field with a spatial resolution of 30nm [48]. The group of Havenith presented a scanning near-field infrared microscopy (SNIM) system this is an IR s-SNOM set-up based on a continuous-wave optical parametric oscillator (OPO) as an excitation source with a much wider tunability compared to the usually applied CO2 lasers [49]. With this set-up, a subsurface pattern of implanted gallium ions in a topographically fiat silicon wafer was imaged with a lateral resolution of <30 nm. 

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