Direct imaging of room temperature optical absorption with subnanometer spatial resolution

Gregory Scott, Sumit Ashtekar, Joseph Lyding, Martin Gruebele

Research output: Contribution to journalArticlepeer-review


Optical absorption can detect individual molecules and nanostructures even in dissipative or strongly quenching environments where fluorescence signals are weak. Here we image optical absorption of individual carbon nanotubes with subnanometer resolution. We show that we can discriminate adjacent nanotubes on a length scale far below the diffraction limit. Then we compare optical absorption imaging of a defect in a single carbon nanotube (CNT) with conventional scanning tunneling microscopy (STM) and conventional current-voltage scan (I-V) bandgap profiles. We directly visualize the penetration depth σ′ = 0.9 ± 0.3 nm of the CNT exciton state into the smaller bandgap region of the defect and derive a size σ = 1.8 ± 0.6 nm for the exciton state. Optical absorption provides a spectroscopic map of molecules simultaneously with conventional STM.

Original languageEnglish (US)
Pages (from-to)4897-4900
Number of pages4
JournalNano letters
Issue number12
StatePublished - Dec 8 2010


  • Carbon nanotubes
  • exciton
  • scanning tunneling microscopy
  • soliton
  • spectroscopy

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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