One Step Closer to an Invisibility Cloak
Normalized magnetic field distribution of a subwavelength metamaterial absorber with plane wave excitation
Metamaterials are artificial media that exhibit a wide range of extraordinary electromagnetic properties that are not found in nature. For example, a negative index of refraction was experimentally verified by R. Smith et al. in 2000 and R. A. Shelby et. al in 2001. Their papers suggest that infinite subwavelength resolution could be achieved by a class of materials, Left-Handed Metamaterials (LHMs). Furthermore, an electromagnetic cloak was experimentally demonstrated using this material by D. Schurig et al. in 2006. Their device used a series of concentric split ring resonators to achieve the desired permittivity and permeability required for a negative index of refraction, but was not effective in visible wavelength.
Recently submitted to arxiv.org is a paper by Christos Argyropoulos, Yan Zhao, and Yang Hao that makes use of these and following experiments to examine several ways that these types of electromagnetic cloaks could be modified to have perfect wave absorption, suitable for operation over a large band of wavelengths, from microwave to optical.
The most interesting part is their conclusion, “It is corroborated that the device is functional with a subwavelength thickness and, hence, advantageous compared to the conventional absorbers. “ This means that such devices would be easily applicable to a wide variety of situations, even maybe clothing! Before you get your hopes up, though, this paper was theoretical, and such applications are probably a decade or two off, at least.
It’s fun to think that such things might be possible in the foreseeable future, though.
Sources:
R. Smith et al., Phys. Rev. Lett. 84, 4184 (2000).
R. A. Shelby et al., Science 292, 7779 (2001).
D. Schurig et al., Science 314, 977980 (2006).
Manipulating the Loss in Electromagnetic Cloaks for Perfect Wave Absorption by Christos Argyropoulos, Yan Zhao, Yang Hao.
This entry was posted on Friday, November 28th, 2008 at 5:07 pm and is filed under Atomic, Molecular, and Optical. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
