Nanoscale near-field

El Ahrach, H. 1., Bachelot, R., Vial, A., Lerondel, G., Plain, J., Royer, P. and Spooera, O. (2007). Spectral degeneracy breaking of the plasmon resnance of single metal nanoparticles by nanoscale near-field photopolymerization. Phys. Rev. Lett. 98 10741 (007) [4 pages]. 

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... 

Yano, T, Inouye, Y. and Kawata, S. (2006) Nanoscale uniaxial pressure effect of a carbon nanotube bundle on tip-enhanced near-field Raman spectra. Nano Lett., 6, 1269-1273. 

To summarize, we have shown here that enhanced electric-field distribution in metal nanoparticle assemblies can be visualized on the nanoscale by a near-field two-photon excitation imaging method. By combining this method and near-field Raman imaging, we have clearly demonstrated that hot spots in noble metal nanoparticle assemblies make a major contribution to surface enhanced Raman scattering. 

Tan W. and Kopelman R. (1996) Nanoscale Imaging and Sensing by Near-Field Optics, in Wang X. F. and Herman B. (Eds), Fluorescence Imaging Spectroscopy and Microscopy, Chemical Analysis Series, Vol. 137, John Wiley Sons, New York, pp. 407-75. 

In this chapter, we showed the capability of near-field optical spectroscopy combined with vibrational spectroscopy and nonlinear optics for biochemical applications. The evanescent field localized at the nanoscale tip realized the extremely small light source for various spectroscopes in the near-field. Especially when the tip is made... 

Science is entering into the nanoscale world, and the organization of microscale or nanoscale biomaterial structures on surfaces has been demonstrated and is a subject of extensive research effort.184,851 Single biomaterial molecules have been imaged on surfaces,186 871 and the individual affinity interactions of biomaterials probed at the molecular level.188,891 While the different scanning microscopy techniques provide useful means to image and manipulate biomaterials on surfaces, the use of the near-field scanning optical microscope (NSOM) 9<) in the activation of photoswitchable biomaterials on surfaces should be emphasized specifically. One... 

SOURCE Reprinted with permission from Teetsov, J.A. and D.A. Vanden Bout. 2001. Imaging molecular and nanoscale order in conjugated polymer thin films with near-field scanning optical microscopy. J. Am. Chem. Soc. 123 3605-3606. Copyright 2001 American Chemical Society. 

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. 

Hwang, J., L.K. Tamm, C. Bohm, T.S. Ramalingam, E. Betzig, and M. Edidin. 1995. Nanoscale complexity of phospholipid monolayers investigated by near-field scanning optical microscopy. Science 270 610-614. 

The first and best known near-field technique to measure electrical properties in the nanoscale is of course Scanning Tunnelling Microscopy (STM). Since its invention by Binnig et al., STM has been used to explore the mechanisms of lots of phenomena on surfaces [289-294], ranging from experiments concerning the local work function to the use of an STM-tip to induce electropolymerisation [295]. Most of all, STM provides us with atomically resolved images of the surface structure. 

Near-field phase shift lithography is a soft lithographic technique used to produce geometric shapes with size features at the nanoscale (approximately 40-80nm).This involves the production of a polymer mask containing the desired pattern to be... 

In addition to being a new route for nanoscale photochemistry, this provides yet another novel means of quantifying the nature of near fields near SPs. 

Abashin M (2009) Near-field characterization of photonic nanodevices near-field scanning optical microscopy (NSOM) characterization of photonic nanodevices and nanoscale optical phenomena. Saarbriicken, Germany... 

Okamoto H, Imura K (2008) Near-field optical imaging of nanoscale optical fields and plasmon waves. Jpn J Appl Phys 47 6055-6062... 

Ichimura T, Hayazawa N, Hashimoto M, Inouye Y, Kawata S (2004) Application of tip-enhanced microscopy for nonlinear Raman spectroscopy. Appl Phys Lett 84 1768 Ichimura T, Hayazawa N, Hashimoto M, Inouye Y, Kawata S (2004) Tip-enhanced coherent anti-stokes raman scattering for vibrational nanoimaging. Phys Rev Lett 92 220801 Tanaka S, Maeda Y, Cai L, Tabata H, Kawai T (2001) Application of tip-enhanced microscopy for nonlinear Raman spectroscopy. Jpn J Appl Phys 40 4217 Watanabe H, Ishida Y, Hayazawa N, Inouye Y, Kawata S (2004) Tip-enhanced near-field Raman analysis of tip-pressurized adenine molecule. Phys Rev B 69 155418 Yano T, Verma P, Saito Y, Ichimura T, Kawata S (2009) Pressure-assisted tip-enhanced Raman imaging at a resolution of a few nanometres. Nature Photon 3 473 Yano T, Inouye Y, Kawata S (2006) Nanoscale uniaxial pressure effect of a carbon nanotube bundle on tip-enhanced near-field Raman spectra. Nano Lett 6 1269 Downes A, Salter D, Elfick A (2006) Heating effects in tip-enhanced optical microscopy. Opt Exp 14 5216... 

However, finding out the position of an object with arbitrary precision is not the same as resolution, which is about separating similar objects at small distances. Localization per se cannot provide superresolution. This is also why, although it had been known and used for decades [109,110] and even routinely applied to single molecules [125,126], localization alone has not provided nanoscale images. (Note that in spite the use of localization in the 1980 s and earlier, near-field optical microscopy still seemed to be the only way to attain nanoscale resolution up to the early 1990 s.) Resolution clearly requires a criterion to discern objects or molecules, the simplest of which is bright vs. dark. ... 

In this chapter, we will review near-field optical methods and their applications to problems in biology and materials science. Near-field techniques provide nanometer spatial resolution by overcoming the Abbe diffraction Hmit, and can be used to investigate many types of sample in situ. Here, emphasis is placed on near-field methods that provide vibrational information (i.e., molecular fingerprints ) of the analytes. Finally, the current challenges faced by these methods and their potential in nanoscale chemical analysis in the near future are discussed. 

The nanostructuring is achieved by directing a pulse from a frequency-tripled Nd YAG laser with a pulse width of 35 ps, a wavelength of 355 nm, and up to 250 pj pulse energy through a near-field optical tip. The tip had a diameter aperture of around 170 nm, creating ablation craters with about the same diameter (see below). Molecular crystals (the same bis-triazene that was used as model compound for the triazene polymers in other studies, shown in Scheme 7) were applied as substrates, because the main goal of this study was the development of nanoscale atmospheric-pressure laser ablation-mass spectrometry [390]. 

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