Tailoring the optical properties at the micro- and nanoscale is key to enable new experiments in the field of quantum optics and biophotonics. To this end, I use my strong background in numerical simulations as well as nano- and microfabrication techniques together with the expertise in spectroscopy, linear and nonlinear optics to enable and conduct experiments.
Waveguiding of surface plasmon polaritons by dielectric-loaded metal structures is studied in detail by combining numerical simulations and leakage radiation microscopy. These types of waveguides are first numerically investigated using the effective index model and the differential method. We analyzed systematically the influence of the ridge width and thickness of the waveguide on the properties of the surface plasmon guided modes. In particular we investigated the confinement factor of the modes and their associated propagation lengths. These two parameters can be optimized by adjusting the thickness of the dielectric layer. Waveguides loaded with thick and thin dielectric ridges are then optically characterized by leakage radiation microscopy. The mode propagation distance is measured by direct-space imaging and the propagation constants are evaluated by Fourier imaging and analysis. Good agreements are found between theoretical and experimental data.
Distance Dependent Spectral Tuning of Two Coupled Metal Nanoparticles
Phillip Olk,
Jan Renger,
Marc Tobias Wenzel,
Lukas M. Eng
The spectral properties of two spherical metallic nanoparticles of 80 nm in diameter are examined with regard to the interparticle distance and relative polarization of the excitation light. One Au nanoparticle is attached to a scanning fiber probe and the second to a scanning substrate. This configuration allows three-dimensional and arbitrary manipulation of both distance and relative orientation with respect to the incident light polarization. As supported by numerical simulations, a periodic modulation of the coupled plasmon resonance is observed for separations smaller than 1.5 µm. This interparticle coupling affects the scattering cross section in terms of spectral position and spectral width as well as the integral intensity of the Mie-scattered light.
