Negative group velocity in layer-by-layer chiral photonic crystals

KH Fung, JCW Lee, CT Chan - arXiv preprint arXiv:0811.1438, 2008 - arxiv.org
KH Fung, JCW Lee, CT Chan
arXiv preprint arXiv:0811.1438, 2008arxiv.org
We study the group velocity of light in layer-by-layer chiral photonic crystals composed of
dielectrics and metals. Through studying the band structures with an extended-zone scheme
that is given by a Fourier analysis, we show the existence of negative group velocity in the
proposed chiral structures. The physical mechanism is interpreted with the help of a
simplified model that has an analytical solution. The iso-frequency contours of the photonic
band structure suggest that the negative group velocity can lead to either positive or …
We study the group velocity of light in layer-by-layer chiral photonic crystals composed of dielectrics and metals. Through studying the band structures with an extended-zone scheme that is given by a Fourier analysis, we show the existence of negative group velocity in the proposed chiral structures. The physical mechanism is interpreted with the help of a simplified model that has an analytical solution. The iso-frequency contours of the photonic band structure suggest that the negative group velocity can lead to either positive or negative refraction, depending on the orientation of the medium interface. We propose a feasible realization of such kind of photonic crystals. Computational results on the proposed realization are consistent with that of the simplified models.
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