Surface Plasmon Polariton Dependence on Metal Surface Morphology
EMSL Project ID
21612
Abstract
Surface Plasmon Polaritons (SPP) are inhomogeneous electromagnetic plane waves bound to the surface of a conductor. Knowledge of SPP characteristics is of timely and critical interest to the rapidly expanding field of SPP-based "Plasmonics." Practical interest derives from the possibility of nano-scale optoelectronic devices, manipulation of optical-pulse propagation, and concentration of electromagnetic energy for sensing applications. These features are all made possible by the strong mode confinement and short wavelengths of SPPs near their frequency limit as compared to guided or free-space electromagnetic waves.The properties of SPPs are determined by their frequency-dependent complex wavevector. This may be calculated from the complex permittivity, which is empirically known for fourteen metals [1]. Numerous reports, from the most recent study [2] to the earliest [3], reveal significant unexplained discrepancies between theory and experiment. These are generally attributed, without analysis or any systematic proof, to surface morphologies, impurities, contamination, and lack of crystallinity for evaporated films. We propose to experimentally determine the complex SPP wavevector over frequencies up to the SPP limit for a number of metal films of varying morphology. These data will be compared with theoretical predictions as a function of several figures of merit that describe the metal surface. This will show if there is in fact any measurable dependence on film quality. If none is found, then the cause of the discrepancies can be narrowed to fundamental flaws in the theory or to incorrect empirical values for the complex permittivity. As a practical outcome, the anticipated data will inform future Plasmonic device fabrication strategies.
The real characteristics of surface Plasmon polaritons (SPP) on metal films will be studied as a function of film quality in EMSL 1221. SPPs will be excited with tunable, visible laser beams and their dispersion relations will be measured. The acquired data from EMSL will be collected with measurements of the imaginary par of the complex wavevectorst studied separately at UCF. These cumulative results will then be compared with theory to inform future nano-photonic device design.
Project Details
Project type
Exploratory Research
Start Date
2007-05-30
End Date
2008-06-01
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members