Near-field and confocal surface-enhanced resonance Raman spectroscopy at cryogenic temperatures.
For laser spectroscopy at variable temperatures with high spatial resolution a combined scanning near-field optical and confocal microscope was developed. Rhodamine 6G (R6G) dye molecules dispersed on silver nano-particles or nano-clusters were investigated. For optical excitation of the molecules, either an aperture probe or a focused laser spot in confocal arrangement were employed. Raman spectra in the wavenumber range between 300 cm-1 and 3000 cm-1 at room temperatures down to 8.5 K were recorded. Many of the observed Raman lines can be associated with the structure of the adsorbed molecule. Intensity fluctuations in spectral sequences were observed down to 77 K and are indicative of single molecule sensitivity.
Anger
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P
Physikalische Chemie, Universität Siegen, 57068 Siegen, Germany Omicron NanoTechnology GmbH, 65232 Taunusstein, Germany. anger@chemie.uni-slegen.de
Feltz
A
A
Berghaus
T
T
Meixner
A J
AJ
D005615:Freezing; D018613:Microscopy, Confocal; D008961:Models, Structural; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*
D012834:Silver