Successful Super-resolution Imaging through a Scattering Super Lens

“In 2013, We developed a nanoparticle-based super lens that had three times the resolution of conventional optical lenses. As an extension of that, we have successfully developed a technology for two-dimensional real-time subwavelength imaging exploiting multiple scattering in nanoparticles. This was through reverse application of a scattering super lens to achieve super-resolution 2D imaging. Research is ongoing on the applications of this technology, firstly, to obtain real-time images of biological samples and, secondly, in optical lithography for semiconductors with even thinner linewidth. This technology has potential applications in ultraprecision optical lithography, super-resolution bio-imaging systems and nano-optical tweezers and is expected foster development in related fields of industry.”

Application in Ultraprecision Optical Lithography and Super-resolution Bio-imaging

Conventional lenses that make use of light refraction to create an optical focus have the limitation of being unable to show objects smaller than 200~300 nanometers within the visible light range. In 2013, Prof. Park YongKeun and his colleagues at KIOST developed the world's first nanoparticle-based super lens technology capable of creating a smaller optical focus than the wavelength of light, to perform at three times the resolution of ordinary optical lenses.
Existing lenses using optical refraction cannot focus on objects smaller than the half of light wavelength, which is so-called the diffraction limit. The scattering super lens, which introduced the concept of near field (information needed to image an object smaller than the wavelength of light) control using multiple scattering in nanoparticles, has the advantage of allowing the generation of small optical foci smaller beyond the diffraction limit. The scattering super lens has made it possible to create light focus four times smaller than the wavelength of light, presenting a new technology which can be potentially applied for optical lithography in semiconductors, nano-optical tweezers, and super-resolution bio-imaging.

Based on their innovative scattering super lens technology, Prof. Park's team has been working on the development of real-time nano-imaging using scattering superlens. After developing the world's first scattering super lens in 2013, the team took their innovation one step further in 2014, reversing the principle of the super lens to observe 2D images of extremely small features of a sample via multiple scattering.

Using ordinary microscopes, it was difficult to distinguish objects below 200 nanometers in size due to the limitation of diffraction, Prof. Park and colleagues have developed a technology that utilizes a scattering superlens to realize real-time full-field subwavelength imaging.

The principle is as follows. Optical nearfields that contains information about small-size particles is converted via multiple scattering into propagating farfields and are recorded using the principle of holography. In general, optical nearfield cannot be delivered via conventional lens based on the principle of light refraction. Light recorded in this manner is used to reconstruct the original image using time reversibility to actualize nano-images that overcome the limits of diffraction.

There have been challenges in accomplishing this technological breakthrough using multiple scattering to produce real-time super-resolution 2D images. In the early stages, there were technical issues in the utilization of near field optical microscopes that had to be overcome, and the foundations for the project were laid with the help of the collaboration team led by Prof. Yong-Hoon Cho in KI graphene center.

The significance of the development of the scattering superlens can be found in a variety of fields. The super-resolution microscope technology, which was awarded last year's Nobel Prize in chemistry, utilized fluorescent proteins to overcome the limitations of light diffraction. The scattering super lens developed by Prof. Park’s team does not need fluorescent proteins, making it possible to take measurements without making modifications to the cells. Thus, it can be utilized as a core technology in all areas requiring optical measurement and control, including the field of light lithography for semiconductor manufacturing.

Moreover, being the first actualization of this principle within the range of visible light, it can also be applied to quality analysis in silicon processes. Above all, it will serve as a part of the nation's intellectual assets as a core technology for handling the conversion of light and obtaining images at the nanoscale.


Prof. Park, Yong-geun
2014 Annual Report