Enhance the resolution of photonic crystal negative refraction imaging by metal grating.
ABSTRACT The resolution of imaging is limited by the missing of high-frequencies information. The superlens employing negative refraction can compensate for these components. But for the directional coupling of Bloch waves and the low coupling efficiency of large-angle waves, the resolution of subwavelength imaging is not satisfactory. However, the subwavelength metallic grating can produce high-order diffracted waves carrying a lot of high-frequencies information. Therefore, this structure is used to inhibit the zero-order diffraction and enhance the high-order diffraction to achieve super-resolution.
Conference Paper: Sub-diffraction linear spatial filtering with layered metamaterials[Show abstract] [Hide abstract]
ABSTRACT: We describe layered metal-insulator metamaterials using the model of a linear-shift-invariant system. We present the modelling and optimisation strategy for engineering such metamaterials. A variety of point spread functions may be reached, either for superresolution, or for far-field image processing. The first group includes layered superlenses and effective media for directed refraction. As an example of the latter, we demonstrate a metamaterial consisting of highly reflecting cavities coupled to form a high-pass spatial filter. The proposed filter can be applied for phase visualisation.Transparent Optical Networks (ICTON), 2012 14th International Conference on; 01/2012
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ABSTRACT: In this paper, super-resolution imaging and negative refraction by a two-dimensional (2D) triangular lattices graded photonic crystal (GPC) were studied. The graded photonic crystal (GPC) was obtained by varying the radius in each row so that its effective refractive index changes along the transverse direction. By using Plane Wave Expansion (PWE) method and Finite-Difference Time-Domain (FDTD) method, we show that negative refraction and superlensing can be realized in the designed graded photonic crystal. Numerical simulations show that the photonic crystal structures and frequency have an impact on the resolution.Progress In Electromagnetics Research M 01/2012; 25. DOI:10.2528/PIERM12070616
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ABSTRACT: Negative refraction attracted great interest and quickly became the subject of extensive worldwide research thanks to the many novel optical phenomena it can enable. One of the most exciting applications of negative refraction is the possibility of imaging with sub-wavelength resolution, which is often called superlensing. Recently, it has been shown that photonic crystals (PhCs) composed of synthetic periodic dielectric materials can exhibit an extraordinarily high nonlinear dispersion which causes effects such as negative refraction and self-focusing properties that are determined by the characteristics of their photonic band structures and equal frequency contours (EFCs). In this paper we have theoretically studied the negative refraction in two-dimensional (2D) triangular lattices graded photonic crystal (GPC) which constructed by varying the photonic crystal parameters so that its effective refractive index changes along the transverse direction of the slab. By using Plane Wave Expansion (PWE) method and Finite-Difference Time-Domain (FDTD) method we have studied the photonic band structure, equal frequency contours and the electric field distribution of the designed graded photonic crystal. Numerical simulations show that negative refraction and superlensing can be realized in the designed graded photonic crystal.Proceedings of SPIE - The International Society for Optical Engineering 10/2012; DOI:10.1117/12.928562 · 0.20 Impact Factor