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Full-Text Articles in Physics

Molecular Fluorescence At A Rough Surface: The Orientation Effects, P.T. Leung, W. L. Blacke Nov 1997

Molecular Fluorescence At A Rough Surface: The Orientation Effects, P.T. Leung, W. L. Blacke

Physics Faculty Publications and Presentations

The problem of the dynamical interaction between an emitting dipole and a metallic grating surface is considered with particular interest in the effects due to different orientations of the dipole with respect to the substrate surface. Our previous perturbative theory is extended to treat both parallel and perpendicular dipoles and the results are applied to the study of modified fluorescence characteristics for admolecules in the vicinity of a rough metal surface modeled as a grating. Numerical results show that some of the characteristics are very sensitive to the molecular orientation and the one along the grating direction is manifested with …


Optical Imaging Of Carrier Dynamics In Silicon With Subwavelength Resolution, Andres H. La Rosa, B. I. Yakobson, H. D. Hallen Jan 1997

Optical Imaging Of Carrier Dynamics In Silicon With Subwavelength Resolution, Andres H. La Rosa, B. I. Yakobson, H. D. Hallen

Physics Faculty Publications and Presentations

Characteristic rate variations of carrier processes are imaged using near-field scanning optical microscopy. We couple both a visible pump and an infrared probe light through a subwavelength aperture to investigate the interband recombination and intraband diffusion of excess carriers in oxidized silicon. Typical values of the locally measured life time constants agree well with those obtained by conventional space-averaged techniques. Moreover, the images locate defects, reveal variations, and can map the regions in which a recombination process is active.


General Remarks On Spectral Entropy Vs. Statistical Entropy, John D. Ramshaw Jan 1997

General Remarks On Spectral Entropy Vs. Statistical Entropy, John D. Ramshaw

Physics Faculty Publications and Presentations

Crepeau and Herzel [1] (CH) have recently compared the spectral entropy of Powell and Percival [2] with the standard statistical (Boltzmann-Gibbs-Shannon) entropy in three simple physical systems. Here we compare and contrast these two entropies in a more general way by considering their values for an arbitrary stationary process X(t).