Single-Molecule Detection of a Cyanine Dye in Silver Colloidal Solution Using Near-Infrared Surface-Enhanced Raman Scattering
| Autor: | Harald Kneipp, Geurt Deinum, Katrin Kneipp, Michael S. Feld, Irving Itzkan, Ramachandra R. Dasari |
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| Rok vydání: | 1998 |
| Předmět: |
Absorption spectroscopy
Chemistry 010401 analytical chemistry Analytical chemistry Laser 01 natural sciences Light scattering 0104 chemical sciences law.invention 010309 optics chemistry.chemical_compound symbols.namesake law 0103 physical sciences symbols Coherent anti-Stokes Raman spectroscopy Cyanine Raman spectroscopy Instrumentation Spectroscopy Raman scattering Excitation |
| Zdroj: | Applied Spectroscopy. 52:175-178 |
| ISSN: | 1943-3530 0003-7028 |
| DOI: | 10.1366/0003702981943275 |
| Popis: | Single-molecule Raman spectroscopy of a cyanine dye in aqueous silver colloidal solution with the use of surface-enhanced Raman scattering at near-infrared excitation (NIR-SERS) is reported. A characteristic Poisson distribution of SERS signals due to the Brownian motion of single dye molecule-loaded silver particles reflects the probability of finding 0, 1, or 2 1,1'-diethyl-2,2'cyanine (PIC) molecules in the probed volume during an actual measurement and is evidence that single-molecule detection by SERS has been achieved. Spectra measured in 1 s collection time with 100 mW nonresonant 830 nm excitation provide a clear “fingerprint” of a single PIC molecule by showing its typical Raman lines between 700 and 1700 cm−1. Single-molecule Raman signals are also detected for the first time at the anti-Stokes side of the excitation laser. Effective Raman cross sections for PIC of ∼10−16 cm2 per molecule can be inferred from the ratio between “pumped” anti-Stokes and Stokes signals. |
| Databáze: | OpenAIRE |
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