We have theoretically modeled and experimentally fabricated a nanoscale adiabatic (conical) metallic structure that is suitable for high-resolution Raman spectroscopy. We report on a fully complex analytical description of the adiabatic compression phenomenon which is investigated in terms of both geometrical and optical parameters. An explicit analytical description of adiabatic compression is provided together with the physical role played by the complex effective refractive index of the polaritonic adiabatic mode. In particular, we have examined the role of absorption on the field enhancement. Finally, we demonstrate how such a device can experimentally enhance the Raman signal coming from nanosamples such as a bead of SiOx and a monolayer of benzenethiol.
Physical Review B
- Pub Date:
- July 2012
- Optical properties of low-dimensional mesoscopic and nanoscale materials and structures;
- Microscopy of surfaces interfaces and thin films;
- Collective excitations;
- Infrared and Raman spectra