Near-field optical imaging of flagellar filaments of salmonella in water with optical feedback control

M. Naya, R. Micheletto, S. Mononobe, R. Uma Maheswari, M. Ohtsu

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We report on the high-resolution observation of biological samples in water with a collection-mode near-field optical microscope (c-mode NOM) operating under optical feedback control. With rapidly decreasing evanescent field power used as the feedback signal, for the first time to our knowledge, an image of straight-type flagellar filaments of salmonella in water has been obtained. The estimated diameter of a single filament is around 55 nm with a pixel size of 10 nm. A comparison with its nominal value of 25 nm obtained from electron microscope observations under high vacuum confirms that our c-mode NOM performs high-resolution imaging in water.

Original languageEnglish
Pages (from-to)1681-1683
Number of pages3
JournalApplied Optics
Issue number7
Publication statusPublished - 1997 Mar 1



  • Biological samples in water
  • Collection mode
  • Evanescent field
  • Near-field optical microscope
  • Optical feedback

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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