"Just as in electronic doping, adding a set of foreign atoms in an otherwise pure material can alter the electronic and optical properties of the host. ‘Photonic doping' means adding a foreign photonic object to a photonic host structure, which can change the optical scattering of the original structure." researcher Nader Engheta said.
The phenomenon works with the epsilon-near-zero (ENZ) materials in which a wave's magnetic field is distributed uniformly.
"If I want to change the way a piece of material interacts with light, I normally have to change all of it," Engheta explained. "Not here. If I place a single dielectric rod anywhere within this ENZ material, the entire structure will look different from the perspective of an external wave."
The dielectric rod is a cylindrical structure made out of an insulating material that can be polarised. When inserted in a 2D ENZ host, it can affect the magnetic field and the optical properties of the material.
Because the wave's magnetic field has a uniform spatial distribution, the dielectric rod can be placed anywhere within the material. Incoming waves behave as if the host material has a different set of optical properties.
According to the team, this could be useful for information processing systems, applications within telecommunications and optical technology, such as flexible photonics.
"The photonic doping can be a new way for us to determine the path this wave takes within a device," Engheta said. "With a small change in the dielectric rod, we can make waves go one way and not another. This should help improve the speed of the device. Adding more rods would allow for even finer tuning of the material's response."
