The optical response of metallic nanoshell which includes coated dielectric particles is investigated in the longwavelength limit in which the nonlocal response of the metal is taken into account. Using our recent formalism which calculates the nonlocal multipole polarizability of such a shell, we have studied how these nanoshells interact with both the far field and near field of a light source. For the far field case, both absorption and scattering cross sections for an incident plane wave are calculated in the dipole approximation. For the near field case, we study how the fluorescence properties of an emitting molecule in the vicinity of a nanoshell are affected, by including all higher multipolar response of the shell. It is found that the nonlocal effects are most prominent for higher order multipoles, and hence for the description of molecules in close proximity interacting with the nanoshell.
We have recently demonstrated that ultra high resolution of angular measurement down to 10-6 degree can be achieved via surface-plasmon-resonance heterodyne interferometry, in which the phase difference between p- and s- polarized reflected waves is monitored as a function of the incident angle. Here we give a brief summary of this technique and the rationale based on which such a measurement is possible. As a further study, we have also investigated, via simulation, how the change in environmental temperature will affect the resolution limit of this very versatile technique.
The theory of pump-probe femto-second time-resolved experiment will be presented. For the case in which the pump and probe pulses do not overlap, the either can be referred to as the generalized linear response theory. The fs time-resolved spectra consist of the contributions from the dynamics of both population and coherence (or phase) of the nonstationary system. Unless the dephasing is fast, the quantum beat is often observed in fs time-resolved spectra. Recently, it has been found that some polymers could exhibit semiconducting properties. In particular, the conjugated polymers, poly (phenylene-vinylene), i.e., PPV, show strong photoluminescence and can form electroluminescent layer in light-emitting diodes (LED). To study the mechanisms of the photoluminescence of PPV, fs time-resolved experiments have been performed. In this paper, the theoretical analysis of these fs time-resolved spectra will be presented. 15
KEYWORDS: Diffraction, Optical properties, Dielectrics, Optical microscopy, Magnetism, Near field scanning optical microscopy, Near field, Optical character recognition, Light wave propagation, Radio propagation
Recent application of tapered fiber tips in near field optical microscopy has demonstrated a resolution far exceed the diffraction limit. We investigate the propagation and tunneling of monochromatic light through a tapered fiber tip near a dielectric surface. The transmission rate through the tip is given for various circumstances and found to increase significantly with the dielectric constant of the sample.