Description:

Raman scattering images of carbon nanotubes (A) using standard diffraction limited microscopy, and (B) using the near-field Raman microscopy technique developed by Lukas Novotny of the University of Rochester and colleagues. The new technique can resolve features as small as 20 nanometers across.

The new method should literally shed light on previously inaccessible chemical and structural information in samples as small as the proteins in a cell's membrane. This is the highest-resolution optical spectroscopic measurement ever made. Although there are other methods that can see smaller structures, none use light, which is rich in information.

To light up the nanoscale, researchers sharpen a gold wire to a point just a few billionths of an inch across. A laser then shines against the side of the gold tip, creating a tiny bubble of electromagnetic energy that interacts with the vibrations of the atoms in the sample. This interaction, called Raman scattering, releases packets of light from the sample that can be used to identify the chemical composition of the material.
 

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