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Chiral Swiss rolls show a negative refractive index
M C K Wiltshire1, J B Pendry, J V Hajnal
1Imaging Sciences Department, Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, Ducane Road, London W12 0NN, UK. The Blackett Laboratory, Department of Physics, Imperial College London, South Kensington, London SW7 2AZ, UK.
Summary
Researchers developed chiral Swiss rolls, a novel metamaterial, exhibiting strong chirality resonant around 80 MHz. This metamaterial shows a negative refractive index and significant circular dichroism.
Area of Science:
- Metamaterials science
- Chiral materials
- Electromagnetics
Background:
- Chiral metamaterials offer unique electromagnetic properties.
- Helically wound structures are key to achieving chirality.
Purpose of the Study:
- To develop and characterize chiral Swiss roll metamaterials.
- To investigate their resonant electromagnetic properties.
Main Methods:
- Fabrication of chiral Swiss roll elements using a custom machine.
- Characterization of permeability, permittivity, and chirality.
- Estimation of refractive indices.
Main Results:
- Chiral Swiss rolls exhibit resonance around 80 MHz.
- Chirality is dominant, exceeding permeability and permittivity.
- Strong circular dichroism observed.
- Negative refractive index demonstrated over a wide frequency range.
Conclusions:
- Chiral Swiss rolls are a promising platform for highly chiral metamaterials.
- The observed properties enable novel applications in optics and electromagnetics.
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