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.
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ABSTRACT: The modal distributions and properties of dielectric and hybrid plasmonic (HP) waveguides are investigated systematically. Their coupling efficiency through a direct coupling scheme is estimated by numerical simulation and the results are compared with values predicted by the Fresnel formula. The influence of various factors on the coupling efficiency between dielectric and HP waveguides, including interface scattering, absorption caused by light coupling to the surface plasmon polariton mode, and the mismatch between the two waveguide modes, is analyzed theoretically. A tapered coupling structure with linearly varying height and width of the silicon layer is proposed, with which extremely high coupling efficiency (94.4%) and good broadband coupling performance (above 90%) are demonstrated.Journal of the Optical Society of America B 06/2013; 30(6):1426-. · 1.81 Impact Factor
- Optik - International Journal for Light and Electron Optics 10/2013; 124(20):4536-4538. · 0.77 Impact Factor
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