Near-field and confocal surface-enhanced resonance Raman spectroscopy at cryogenic temperatures |
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Authors: | P Anger† A Feltz† T Berghaus† & A J Meixner |
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Affiliation: | Physikalische Chemie, Universität Siegen, 57068 Siegen, Germany; Omicron NanoTechnology GmbH, 65232 Taunusstein, Germany |
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Abstract: | 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. |
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Keywords: | Confocal microscopy low temperature nano-particles near-field optical microscopy rhodamine 6G surface-enhanced resonance Raman effect |
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