AsianScientist (Dec. 8, 2014) – Using a metamaterial, scientists have developed a technology that can manipulate a polarized light in broadband operations. It is expected that this technology will lead to the development of optical devices that can be applied to broadband communication and displays. The study documenting these findings has been published in Nature Communications.
When an object or its structure is analyzed by using polarized light such as a laser, the results are affected by the polarized state of the light. To manipulate the polarity of light, researchers employ wave plates or photoactive materials. However, the performance of these devices depend vastly on wavelength, and so they are not suitable to be used as a polarizer, especially in broadband.
There have been many attempts to make artificial materials that are very photoactive by using metamaterials which have a property known as resonance. However, because the materials used to date have an unavoidable dispersion in the resonance frequency, they are not suitable for broadband operations.
In the present study, Professor Min Bumki from the Korea Advanced Institute of Science and Technology (KAIST) and his research team arranged and connected helical metamaterials that are smaller than the wavelength of light. Using super-thin materials less than one-tenth the thickness of the wavelength of the light, they demonstrated theoretically and experimentally that polarized light can be constantly rotated regardless of the wavelength used.
Broadband polarized rotational 3D metamaterials were found to rotate the polarized microwave within the range of 0.1 GHz to 40 GHz by 45 degrees regardless of its frequency. This non-dispersive property is quite unnatural because it is difficult to find a material that does not change in a wide range of wavelengths.
In addition, the research team realized the broadband non-dispersive polarized rotational property by designing the metamaterial in a way that it has chirality, which determines the number of rotations proportional to the wavelength.
Min said, “As the technology is able to manipulate ultrathin polarization of light in broadband, it will lead to the creation of ultra-shallow broadband optical devices.”
The article can be found at: Park et al. (2014) Nondispersive Optical Activity of Meshed Helical Metamaterials.
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Source: KAIST.
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