21 research outputs found
The missing ingredient in effective-medium theories: Standard deviations
Effective-medium theories for electromagnetic constitutive parameters of
particulate composite materials are theories of averages. Standard deviations
are absent because of the lack of rigorous theories. But ensemble averages and
standard deviations can be calculated from a rigorous theory of reflection by
planar multilayers. Average reflectivities at all angles of incidence and two
orthogonal polarization states for a multilayer composed of two kinds of
electrically thin layers agree well with reflectivities for a single layer with
the same overall thickness and a volume-weighted average of the relative
permittivities of these two components. But the relative standard deviation can
be appreciable depending on the angle of incidence and the polarization state
of the incident illumination, and increases with increasing difference between
the constitutive parameters of the two layers. This suggests that average
constitutive parameters obtained from effective-medium theories do not have
uniform validity for all calculations in which they might be used.Comment: 12 pages (accepted for publication in Journal of Modern Optics
Scattering and absorption cross sections of light diffusing materials retrieved from reflectance and transmittance spectra of collimated radiation
Practical Implementation of Accurate Finite-Element Calculations for Electromagnetic Scattering by Nanoparticles
Defining disrespect and abuse of newborns: a review of the evidence and an expanded typology of respectful maternity care
Are maternal healthcare services accessible to vulnerable group? A study among women with disabilities in rural Nepal
Coherence converting plasmonic hole arrays
Simulations are presented that demonstrate that the global state of spatial coherence of an optical wavefield can be altered on transmission through an array of subwavelength-sized holes in a metal plate that supports surface plasmons. It is found that the state of coherence of the emergent field strongly depends on the separation between the holes and their scattering strength. Our findings suggest that subwavelength hole arrays on a metal film can be potentially employed as a plasmon-assisted coherence converting device, useful in modifying the directionality, spectrum, and polarization of the transmitted waveSupport EWElectrical Engineering, Mathematics and Computer Scienc