Condensed Matter (Theoretical)
This research will study electrodynamics near surfaces with the goal of further fundamental understanding and contact with experiments. The primary effort will be on the linear response of surfaces to an applied field. For clean, flat surfaces we make use of the d- parameter formalism. A wider range of frequencies will be studied, and various paths away from jellium models will be developed so that effects of discrete atomic structure can be incorporated into the model. The resulting theory will be applied to systems ranging from simple metals to multiple quantum wells. A parallel effort will be made to transfer the model developed to nonlinear response properties such as second harmonic generation or photon drag at surfaces of cubic materials. We also will develop theories for systems with structured overlayers, such as gratings and frequency selective surfaces. The aim is to develop tractable computational schemes that allow one to describe both qualitatively and quantitatively the coupling efficiency as a function of material properties and topological arrangements.
We have developed computer codes to treat the optical behavior of simple frequency-selective surfaces. The key simplification is that the surface structures are thin compared to the wavelength of light. Using an overview based on standing waves, calculations over a wide spectral range (infrared to visible) have been carried through and successfully compared with experiment.
For more general configurations, we have also developed codes that use the finite-difference-time-domain (fdtd) method. These allow simulations of the reflection, transmission and absorption behavior of arbitrarily nanostructured surfaces and interfaces. The codes are being used to help design and interpret several near-field optics experiments.
Condensed Matter, Near-field Optics, Optics, Physics, Solid State, Surface Physics, Synchrotron Radiation
