Abstract
We present the first multiwavelength surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) study, as well as the first observation of anti-Stokes vibrational features in SE-FSRS spectra. We compare stimulated Raman loss (SRL) and stimulated Raman gain (SRG) signals at three pump wavelengths chosen to sample different portions of nanoparticle aggregate localized surface plasmon resonances. The SE-FSRS signals exhibit similar signal magnitudes in the SRL or SRG regions of the spectra regardless of Raman pump or probe wavelength. The spectral lineshapes, however, differ dramatically with excitation wavelengths. The observed trends in spectral line shape show a strong dependence on the relative position of the excitation fields with respect to the plasmon resonance but do not match predictions from any existing SE-FSRS theory. These results suggest the need for further theoretical efforts with complementary experimental studies of individual aggregates to remove the effects of inherent ensemble averaging.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3328-3333 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 8 |
| Issue number | 14 |
| DOIs | |
| State | Published - Jul 20 2017 |
Funding
L.E.B. M.O.M., N.L.G., G.C.S., and R.P.V.D. were supported by the National Science Foundation (NSF) Center for Chemical Innovation (CCI) dedicated to Chemistry at the Space Time Limit (CaSTL) Grant CHE-1414466. Ms.O.M. and N.L.G acknowledge support from the NSF Graduate Research Fellowship Program (DGE-0824162). All instrumentation used in these experiments was purchased by NSF CCI - CaSTL Grant CHE-1414466.
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry