New Superlens Breaches The Diffraction Limit

Scientists have developed a lens that can beat the diffraction limit, enabling ultra-high resolution imaging.

AsianScientist (Oct. 3, 2014) – A joint research team led by Professors Park Yongkeun and Cho Yong-Hoon from the Korea Advanced Institute of Science and Technology (KAIST), has succeeded in capturing real-time 2D images at a resolution of 100 nm (nanometers).

This level of resolution was previously impossible with optical lenses due to the diffraction limit of light. The research, published in Physical Review Letters, could be applied to high-precision semiconductor manufacturing process or observation of intracellular structures.

Since optical lens utilize the refraction of light, the diffraction limit—the inability to focus on scales smaller than the wavelength of light—has always been a barrier to acquiring high-resolution images. Because of the diffraction limit, it was impossible to observe objects less than the size of 200 to 300 nm in the visible light spectrum.

In order to solve the problem of near-field extinction due to scattering of light, the research team used spray paint consisting of nano-particles massed with dense scattering materials to obtain high-resolution information.

By calculating and restoring the first scattering shape of light using the time reversibility of light, the researchers were able to overcome the diffraction limit. The original position of an object observed is obtained by deriving the complex trajectory of the light and reversing the time to locate the particular position of the object.

“This new technology can be used as the core technology in all fields which require optical measurement and control. The existing electron microscopy cannot observe cells without destroying them, but the new technology allows us to visualize at ultra-high resolution without destruction,” Prof. Park said.

The article can be found at: Park et al. (2014) Full-Field Subwavelength Imaging Using a Scattering Superlens.

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Source: KAIST.
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