Now you see it, now you don’t. An optical chip has been rendered invisible by researchers at Ben-Gurion University of the Negev, Israel. Their cloaking method relies on silicon photonics integrated circuits which deflect and scatter light away from the “cloaking” chip’s surface so it is not detected.
According to the researchers, an operational cloaking chip can be an extension of the basic technologies such as radar-absorbing dark paint used on stealth aircraft, local optical camouflage, surface cooling to minimize electromagnetic infrared emissions, or electromagnetic wave scattering.
"These results open the door to new integrated photonic devices, harnessing electromagnetic fields of light at nanoscale for a variety of applications from on-chip optical devices to all-optical processing," said Dr. Alina Karabchevsky, head of the university’s Light-on-a-Chip Group and a member of the university’s Unit of Electro-Optical Engineering and the Ilse Katz Institute for Nanoscale Science and Technology. "We showed that it is possible to bend the light around an object located on the cloak on an optical chip. The light does not interact with the object, thus resulting in the object's invisibility."
"We proposed the new composite plasmonic waveguide scheme with dielectic nano-spacer based on the transformation optics principles to manipulate with light and distort the evanescent fields in a controllable manner to conceal an object," the researchers explained in Nature Scientific Reports. "The plasmonic metasurface is placed on the composite plasmonic waveguide with the nano-spacer. High dielectric nano-spacer made of Si has contributed to the light confinement in vicinity with the metasurface boundary and facilitated the coupling to the hybrid plasmonic modes. The light manipulation is realized due to the engineered effective permittivity which in turn avoids the scattering effect."