Exotic Material Facilitates High-Resolution Microscopy
A paper by a group of RWTH researchers led by Professor Thomas Taubner of the Department of Metamaterials and Nano-Optics was published on June 26 in the high-impact journal Nature Communications.
The paper, entitled “Hyperbolic phonon-polaritons in boron nitride for near-field optical imaging and focusing”, describes optical properties of the exotic natural material boron nitride which so far have only been reported for artificial materials. In their experiments, conducted jointly with a research team around Nobel Prize winner Konstantin Novoselov, the researchers utilized a new laser developed at the Fraunhofer Institute for Laser Technology, ILT.
The material boron nitride is a so-called two-dimensional material that is mechanically stable in one monolayer. Two-dimensional materials are attracting significant attention in physics, chemistry and nanotechnology due to their unique electrical and optical characteristics.
Thomas Taubner and his team demonstrate that certain effects can be utilized in microscopy. With the help of the new material, objects can be imaged which are significantly smaller than the natural wavelength of the used light. In this way, a thin layer of hexagonal boron nitride serves as a “superlens” which is able to image very small objects in a scale of 1:1.
The material, however, is also capable of generating the enlarged contour of a nano-object – a standard superlens cannot achieve this. This lays the basis for larger super lenses made of natural materials. So far, this was only possible using artificial materials.