Scanning near-field optical microscopy on rough surfaces: Applications in chemistry, biology, and medicine
Shear-force apertureless scanning near-field optical microscopy (SNOM) with very sharp uncoated tapered waveguides relies on the unexpected enhancement of reflection in the shear-force gap. It is the technique for obtaining chemical (materials) contrast in the optical image of “real world” surfaces...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2006-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/IJP/2006/69878 |
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| Summary: | Shear-force apertureless scanning near-field optical microscopy
(SNOM) with very sharp uncoated tapered waveguides relies on the
unexpected enhancement of reflection in the shear-force gap. It is
the technique for obtaining chemical (materials) contrast in the
optical image of “real world” surfaces that are rough and very
rough without topographical artifacts, and it is by far less
complicated than other SNOM techniques that can only be used for
very flat surfaces. The experimental use of the new photophysical
effect is described. The applications of the new technique are
manifold. Important mechanistic questions in solid-state chemistry
(oxidation, diazotization, photodimerization, surface hydration,
hydrolysis) are answered with respect to simultaneous AFM (atomic
force microscopy) and detailed crystal packing. Prehistoric
petrified bacteria and concomitant pyrite inclusions are also
investigated with local RAMAN SNOM. Polymer beads and unstained
biological objects (rabbit heart, shrimp eye) allow for nanoscopic
analysis of cell organelles. Similarly, human teeth and a
cancerous tissue are analyzed. Bladder cancer tissue is clearly
differentiated from healthy tissue without staining and this opens
a new highly promising diagnostic tool for precancer diagnosis.
Industrial applications are demonstrated at the corrosion behavior
of dental alloys (withdrawal of a widely used alloy, harmless
substitutes), improvement of paper glazing, behavior of blood bags
upon storage, quality assessment of metal particle preparations
for surface enhanced RAMAN spectroscopy, and determination of
diffusion coefficient and light fastness in textile fiber dyeing.
The latter applications include fluorescence SNOM. Local
fluorescence SNOM is also used in the study of partly aggregating
dye nanoparticles within resin/varnish preparations. Unexpected
new insights are obtained in all of the various fields that cannot
be obtained by other techniques. |
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| ISSN: | 1110-662X 1687-529X |