Mechanism of the large polarization rotation effect in the all-dielectric artificially chiral nanogratings

Department of Physics and Mathematics, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland.
Optics Express (Impact Factor: 3.49). 02/2009; 17(2):688-96. DOI: 10.1364/OE.17.000688
Source: PubMed


The physical mechanism of the large polarization rotation effect in direct transmission of the all-dielectric artificially chiral nanogratings is explored by experiment and numerical analysis. It is shown that the different coupling of right- and left-circularly polarized components of the normally incident light to the leaky guided modes or Fabry-Pérot resonance modes lead to the enhanced circular dichroism, resulting in the giant polarization rotation effect. The mode profile and local field calculations demonstrate intuitive images of the different coupling performance at resonances.

Download full-text


Available from: Yuri Svirko, Oct 13, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present a mathematical model and its numerical implementation for the analysis of the interaction of spatially partially coherent electromagnetic fields with micro- and nanostructured objects. The model is based on the decomposition of the incident field into a set of fully coherent but mutually uncorrelated elementary field modes, and the use of the Fourier Modal Method (FMM) with the S-matrix propagation algorithm. We apply the model to studies of the excitation of surface plasmons in thin metallic slabs, nanowires, and resonant structures. We demonstrate, e.g., that the plasmon excitation efficiency is not essentially affected by the degree of spatial coherence. However, certain plasmon interference effects can be efficiently smoothed out by using illumination with reduced coherence.
    Applied Physics B 10/2010; 101(1):273-282. DOI:10.1007/s00340-010-4012-z · 1.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrated large optical activity in the zeroth-order transmission with metal and dielectric planar chiral nanogratings enhanced by surface-plasmon or waveguide resonances; and observed circularly-polarized emission from the semiconductor chiral nanogratings with quantum dots.
    Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009. CLEO/PACIFIC RIM '09. Conference on; 01/2009
  • [Show abstract] [Hide abstract]
    ABSTRACT: When a linearly polarized light wave propagates in a chiral medium, the polarization plane azimuth rotates clockwise or counter-clockwise depending on the handedness of the material. This effect is called optical activity. It can be observed in a number of crystals and organic liquids, however the rotatory power of chiral materials available in nature is useally very small. That is why chiral planar micro- or nano-structures, which possess a much stronger rotatory power than natural chrial media, have attracted a considerable attention in recent years. We demonstrate large optical activity of chiral subwavelength gratings having no in-plane mirror symmetry and fabricated with metal thin films. For zeroth-order transmitted light, the chirality of these gratings manifests itself in the non-coplanarity of the electric field vectors at the air- and substrate-sides of the metal layer and can be interpreted in terms of the surface pllasmon enhanced non-local light-matter interaction. We demonstrate also that in all-dielectric subwavelength chiral gratings, the optical activity can be enhanced even stronger by using waveguide resonance. In the terahertz (THz) region, we obtain rotation of the polarization zimuth of a linearly polarized THz wave by using double-layered metal chiral structure with complimentary patterns.
    Proceedings of SPIE - The International Society for Optical Engineering 08/2009; 7395:19-. DOI:10.1117/12.827004 · 0.20 Impact Factor
Show more