SERS-active nanoaggregates observed with near-infrared laser excitation

D. J. Maxwell, S. Nie

Research output: Contribution to journalConference articlepeer-review


Using wide-field illumination, optically active "hot" particles can be screened from a heterogeneous colloid using a near-IR excitation source. Atomic force microscopy (AFM) correlated with surface-enhanced Raman scattering (SERS) measurements reveal that the majority of these particles are small nanoparticle aggregates. This finding indicates a strong dependence between particle size and Raman enhancement. Furthermore, these "hot" nanoaggregates display an intermittent on-off emission behavior similar to "blinking" SERS exhibited at 488 nm and 514 nm laser excitation. This behavior, not observed in bulk SERS studies, can only be examined at the single particle level because of variations in particle size, shape, and surface defects. Further examination at the single particle level using a near-IR excitation source could led to new insights regarding the fundamental nature of "hot" particles as well as the SERS mechanism.

Original languageEnglish (US)
Pages (from-to)55-62
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jan 1 2001
Externally publishedYes
EventNanoparticles and Nanostrutured Surfaces: Novel Reporters with Biological Applications - San Jose, CA, United States
Duration: Jan 24 2001Jan 25 2001


  • Nanoparticles
  • Near-infrared
  • SERS
  • Surface-enhanced Raman scattering

ASJC Scopus subject areas

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


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