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The control of light at the nano-level Professor Min Bumki Professor Min Bumki’s research team from the Department of Mechanical Engineering at KAIST have successfully gained control of the transmittance of light in optical devices using graphene* and artificial 2-dimensional metamaterials**. * Graphene : a thin membrane composed of pure carbon, with atoms arranged in a regular hexagonal pattern ** Metamaterials : artificial materials engineered to have properties that may not be found in nature The research results were published in the recent online edition (September 30th) of Nature Materials, a sister journal of the world renowned Nature journal, under the title ‘Terahertz waves with gate-controlled active graphene metamaterials’ Since the discovery of graphene in 2004 by Professors Novoselov and Geim from the University of Manchester (2010 Nobel Prize winners in Physics), it has been dubbed “the dream material” because of its outstanding physical properties. Graphene has been especially praised for its ability to absorb approximately 2.3% of near infrared and visible rays due to its characteristic electron structure. This property allows graphene to be used as a transparent electrode, which is a vital electrical component used in touch screens and solar batteries. However, graphene’s optical transmittance was largely ignored by researchers due to its limited control using electrical methods and its small optical modulation in data transfer. Professor Min’s team combined 0.34 nanometer-thick graphene with metamaterials to allow a more effective control of light transmittance and greater optical modulation. This graphene metamaterial can be integrated in to a thin and flexible macromolecule substrate which allows the control of transmittance using electric signals. This research experimentally showed that graphene metamaterials can not only effective control optical transmittance, but can also be used in graphene optical memory devices using electrical hysteresis. Professor Min said that “this research allows the effective control of light at the nanometer level” and that “this research will help in the development of microscopic optical modulators or memory disks”. figure 1. The working drawing of graphene metamaterials figure 2. Conceptual diagram (Left) and microscopic photo (right) of graphene metamaterials
2012.11.23 View 9929

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