Observation of DNA fixed on a sapphire substrate by a collection mode near-field optical microscope

Uma Maheswari Rajagopalan, Shuji Mononobe, Kenji Yoshida, Mamoru Yoshimoto, Motoichi Ohtsu

Research output: Contribution to journalConference articlepeer-review


We present the observation results of a single string DNA (deoxy ribo nucleic acid) obtained by collection mode near-field optical microscope (NOM) operated under constant distance mode with the optical near field intensity as the feedback signal. The observed width of the narrowest string is 4 nm. To our knowledge, this is not only the successful optical observation of a single string DNA by purely optical means but also under such high resolving capability. These are attributed to the special care taken during the sample preparation to avoid unwanted scattered light and to the probe which were specially designed to enhance the local near field interaction. All these factors make the probe picks up efficiently the high spatial frequency components of the scattered near field at the same time rejecting effectively the lower spatial frequency components.

Original languageEnglish
Pages (from-to)446-451
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1999
Externally publishedYes
EventProceedings of the 1998 International Conference on Optics and Optoelectronics - Silver Jubilee Symposium of the Optical Society of India - Dehradum, India
Duration: 1998 Dec 91998 Dec 12

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Observation of DNA fixed on a sapphire substrate by a collection mode near-field optical microscope'. Together they form a unique fingerprint.

Cite this