Super Imaging With a Plasmonic Metamaterial:

1. Super Imaging With a Plasmonic Metamaterial: Role of Aperture Shape Shiyi Xiao, Qiong He, Xueqing Huang, Lei Zhou* Physics Department, Fudan University, Shanghai, 200433, China I. Motivations: IV. Isotropic Fractal-like HMP Super-lens Holy metallic plates with different aperture-shape were recently suggested to realize subwavelength imaging. J. Jung , et al., Phys. Rev. B 79,153407 (2009). PROBLEMS ! • The role played by the aperture shape is not elucidated. • Structure is anisotropic. X. Huang, et al., Opt. Express 18, 10377 (2010). Fig.6 square aperture with different thickness II. Theoretical Analysis of the Aperture Shape’s Role III. Numerical verification To Identify the Conditions =0.2 High Trans. Freq. Suppose a source: =0.9 Fixed The E-field of image plane is found explicitly as: Fig. 5 S0 of the fractal aperture High Trans. Freq. Unfixed Fig.2 square aperture with different thickness (Fixing cut off Freq.) Only a/d→0 1. High Trans. occurs at the cut off Freq. 2. Phase change is zero and are the transfer functions Fig. 7. Amplitude (squares) and phase (dashed line) of the transfer functions the image plane is identical tothe source plane Fig. 1 super imaging For HMP: GOOD Resolution Fig.3 (a) High Trans. freq. and (b) the phase changes for square-aperture HMPs with different a/d. Here, is the admittance Wave vector Fig.8. FDTD calculated E-field pattern on the image plane of a 5-mm thick fractal-aperture HMP, Smaller S0 BetterCut-off mode Better Image is the overlapping integral. (Structure is deep sub-wavelength) When , (cut off mode) V. Conclusions: In short, we found two analytical conditions for such systems to work as super lenses. We employed FDTD simulations to study the imaging functionalities of two types of super lenses, and found that the aperture shape plays a crucial role in achieving the super imaging effect. Eq. (1) Fig.4 E-field image patterns of square-aperture HMPs with different values of a/d: (a) a/d =0.9,(b) a/d =0.5, (c) a/d =0.3 and (d) a/d =0.1. Two analytical conditions: I II [1]S. Xiao, et al., Metamaterials (2011) doi:10.1016/j.metmat.2011.03.005