Dispersion coding of ENZ media through a number of photonic dopants

Media with small permittivity, i.e., the epsilon-near-zero (ENZ) media, have drawn an excessive amount of consideration from the fields of physics, supplies science, and engineering. The wavelength in ENZ medium is in precept infinitely stretched, which induces spatially static whereas temporally oscillating wave dynamics.

There has lengthy been a drive to realize the versatile manipulation of ENZ media and create real-world purposes. Recent years have seen the rise of metamaterials, the place researchers use periodically-arranged synthetic items or resonators to regulate the efficient constitutive parameters of the composite medium. However, it stays a thriller how an ENZ medium comprising a number of resonators would behave, and the way these resonators work together by means of the ENZ background.

In a paper newly printed in Light: Science & Applications, a workforce of scientists, led by Professor Yue Li from Department of Electronic Engineering, Tsinghua University, China, becoming a member of forces with the Public University of Navarre, Spain, and the University of Pennsylvania, U.S., revealed an unique phenomenon in ENZ media.

They demonstrated that a number of densely-packed dielectric rods, named photonic dopants, can supply noninteracting resonant modes whereas nonetheless being coupled to the exterior setting. The habits of those “noninteracting resonators” was counterintuitive and it contrasted with that of typical microwave and optical resonators. Both the speculation and experiments confirmed that ENZ medium comprising a number of dielectric dopants can exhibit a “comb-shaped” dispersion of the efficient permeability operate, and, remarkably, every “tick” within the frequency comb may very well be related to one particular dopant and might be altered independently.

The scientists proposed the strategy of dispersion coding for ENZ media. By selecting the presence or absence of every dielectric dopant, one can independently management the responses of the ENZ medium at a sequence of frequencies. The scientists introduced two fascinating purposes of the dispersion coding.

The first is the optical tagging the place totally different combos of dielectric dopants can characterize totally different info sequence, and the second is a digitally reconfigurable comb-profiled filter. The scientists summarize the important thing factors of the strategy of dispersion coding for ENZ media:

“(1) As an important difference from the periodic metamaterials, the effective parameter (effective permeability) of the doped ENZ medium is entirely determined by the characteristics of the unit cells, i.e., the dielectric dopants, and not by their positions. (2) The contributions from the noninteracting dielectric dopants to the whole ENZ medium are additive, which substantially simplify the design of artificial composite materials.”

“In the future, the technique of dispersion coding can be used for the muti-frequency analog signal processing in terahertz and even optical regimes. Since the shape of ENZ media as well as the spatial arrangement of dielectric dopants have no influence on the effect of dispersion coding, one is able to realize ultra-compact and highly-integrated devices for the high-frequency signal processing and filtering,” the scientists stated.