Anisotropy of near-field speckle patterns

Field Correlations in Surface Plasmon Speckle

In this work fluctuations in the electric field of surface plasmon polaritons undergoing random scattering on a rough metallic surface are considered. A rigorous closed form analytic expression is derived describing second order correlations in the resulting plasmon speckle pattern assuming statistically stationary and isotropic roughness. Partially coherent planar Schell-model source fields can also be described within the developed framework. Behaviour of the three-dimensional degree of cross polarisation and spectral degree of coherence is also discussed. Expressions derived take full account of dissipation in the metal with non-universal behaviour exhibited within the correlation length of the surface and source fields.

Observation of vortices and field correlations in the near-field speckle of a three-dimensional photonic crystal

We present a phase-sensitive near-field study of speckle fields from photonic crystals in the presence of disorder. We observe phase singularities (vortices) and analyze their statistical properties and screening effects. The experimental results show a clear polarization dependence, not only in their morphological parameters but also in their spatial distribution.