|Publication No: 711P||Search all ORC publications|
Asymmetric diffraction from regular, quasi-random fractal planar chiral nanostructures
A.Papakostas, A.S.Schwanecke, A.Potts, S.L.Prosvirnin*, D.M.Bagnall, N.I.Zheludev
University of Southampton, UK
* National Academy of Science, Ukraine
Planar chiral structures are an intriguing new type of optical meta-material which offer the possibility of effective manipulation of the polarization state of light in the far and near fields, as well as manifesting a range of new phenomena such as 2D optical activity. They also promise intriguing new properties such as nonreciprocal diffraction and time non-reversal light scattering.
In this paper we report the first experimental results on the study of the symmetric and vectorial properties of light fields diffracted from arrays of regular, quasi-random and fractal planar chiral structures manufactured in thin metallic and dielectric films. We have observed a range of previously undocumented phenomena. these include the observation of a reduction in the order of symmetry of the diffracted field distributions compared with the symmetry of the diffraction gratings themselves when studied using polarized light, polarization sensitivity of the diffracted field distributions, and the formation of quasi-random chiral field maps in diffraction from irregular chiral arrays.
In addition, we have developed a new continuous chirality measure and, for the first time, simultaneously evaluated the chirality of diffraction gratings and of the corresponding field distribution of light diffracted from them. We also define symmetry groups for both the arrays and their corresponding diffraction patterns. The experimental results are compared with computer simulations of scattered field.
Photon '04 / QEP-16 Glasgow, UK 6 - 9 Sep (2004)
Publisher′s URL: Only abstract available
Southampton ePrint id: 57764
Copyright University of Southampton 2006