1. High transmission through high index metamaterial
Zhengyong Song, and Lei Zhou
Surface Physics Laboratory (State Key Laboratory) and Department of Physics,
Fudan University, Shanghai , China
Abstract: The metamaterial consisting of thin layers of alternating positive and negative permittivity will respond to electromagnetic radiation as a homogeneous effective medium with anisotropic dielectric permittivity[1], at least in the long wavelength limit. When electric field is perpendicular to this 1D periodic structure along lateral direction, the behavior of this system becomes very interesting: the existence of resonance phenomenon definitely leads to the occurrence of high index[2] at some specific frequency, which is very scarce in natural material. We can tune the resonance frequency either by altering the plasma frequency of metallic mesh structure or by changing the ratio of layer thicknesses. Furthermore, the thing which makes us amusing is that high transmission is observed in ABA structure[3] by this resonance. Using finite-difference-time-domain (FDTD) simulation, we design a metallic net structure to realize this idea. In the near future, microwave experiments will be performed to verify our predictions.
1D periodical structure
The occurrence of high index
The left : System geometry. The layers are infinite in extent
in the xy plane.
The right: the equivalent effective media model.
Metallic Net Structure
This introduces a mechanism for creating artificial high refractive index metamaterials.
Reflection and Transmission
ABA structure with different air gaps
between layers A and B
Rigorous criterion for perfect transmission
If the gap is bigger than the critical thickness, no perfect transmission exists and the maximum transmittance is less than unity.
References:
[1] D. Bergman, Physics Reports 43, 377 (1978).
[2] J. T. Shen, Peter B. Catrysse, and Shanhui Fan, Physical Review Letters 94, (2005).
[3] Lei Zhou, Weijia Wen, C. T. Chan, and Ping Sheng, Physical Review Letters 94, (2005).