Raman scattering and fluorescence emission in a single nanoaperture: Optimizing the local intensity enhancement |
| |
Authors: | Jérôme Wenger José Dintinger Evgeni Popov Thomas W Ebbesen |
| |
Institution: | a Institut Fresnel, Université d’Aix-Marseille III, CNRS UMR 6133, Domaine Universitaire de Saint Jérôme, 13397 Marseille Cedex 20, France b ISIS, Université Louis Pasteur, CNRS UMR 7006, 8 allée G. Monge, 67000 Strasbourg, France c Commissariat à l’énergie atomique, Centre d’études scientifiques et techniques d’Aquitaine, BP2, 33114 Le Barp, France |
| |
Abstract: | We investigate the potential of a single subwavelength aperture milled in an aluminium film to enhance the local electromagnetic field. We compare the Raman scattering of unadsorbed chlorobenzene molecules and the fluorescence emission of Cyanine-5 dyes, having the same excitation and collection setup for both experiments. For the optimal nanoaperture diameter, we report a clear enhancement factor of about 5 of the Raman scattering intensity per unit volume. Since Raman scattering probes the molecular vibrational levels and avoids the resonant pumping of a real excited state, the observed Raman enhancement is disconnected from the effects of the molecular energy levels alteration previously reported for fluorescent dyes. The observations are similar for both Raman and fluorescence experiments, and stand in good agreement with numerical electromagnetic computations of the excitation intensity inside the nanoaperture. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|