2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Combining optical spectroscopy and microscopy to image objects smaller than the size of the focal point

A.G. Walsh, W. Bacsa, A.K. Swan
CEMES, Univ. Toulouse, FR

optical microscopy, optical spectroscopy, nanotubes, Raman spectroscopy

Individual suspended carbon nanotubes represent a unique system to learn about the microscopy and spectroscopy of objects smaller than the diffraction limited focal point of lens based optical systems (1). Suspended carbon nanotubes can be grown on lithographically prepared trenches and enable recording spectra of objects 1 nm wide without substrate signal. By recording Raman spectra form individual carbon nanotubes we find that spectral position of the Raman bands depend on the location of the nanotube with respect to the optical axis and the tube direction with respect to the direction of the optical slit or grating grooves. This has the consequence that the spectral position contains information of the location of the nanotube in the focal plane and demonstrates that optical microscopy and microscopy are related to each other when observing objects smaller then the size of the focal point. We find, in addition that the spectral line width can be narrower then what is expected from the slit size of the grating spectrometer. This is seen in the radial breathing modes of single wall carbon nanotubes. (1) Y. Yin, A. G. Walsh et al. IEEE J of Selected Topics in Quantum Electronics, Vol 12 (2006) 1083

Nanotech 2008 Conference Program Abstract