General Impedance Matching via Doped Epsilon-Near-Zero Media

Abstract

The emerging technique of photonic doping endows epsilon-near-zero (ENZ) media with a broadly tunable effective magnetic permeability. In this work, we theoretically and experimentally demonstrate that a finite-size doped ENZ region counterintuitively behaves as a lumped circuit element, modelled as a controllable series reactance. Based on this concept, a general matching network is constructed to match a load with arbitrary complex impedance, while interestingly its operating bandwidth can also be modified by fine-tuning the dopants' properties. To demonstrate the universality of the concept, different kinds of loads are matched, including microwave circuits, antennas, and absorbing particles. Since this technique is not limited to a specific type of load, nor a specific geometry, and can be readily transplanted from microwave to optical regimes, the proposed methodology facilitates impedance matching for maximum usage of power in quite general scenarios, and thus exhibits promising potential for broad applications.

Dirac-like cone-based electromagnetic zero-index metamaterials

“…An arbitrarily shaped 2D ENZ medium doped with several 2D macroscopic nonmagnetic dielectric dopants is equivalent to a 2D homogeneous medium with the same shape, a near-zero effective permittivity, and an effective permeability determined by the geometric and material parameters of the dopants [16][17][18][19] . When the dopants' parameters equal to certain values, the effective permeability equals to zero, leading to an EMNZ behavior near the plasma frequency of the ENZ host.…”

“…Spatially continuous ENZ can be achieved across a bulk metal near the plasma frequency 2,13,14 . Distinct from the spatially continuous ENZ, macroscopic EMNZ can be realized by traditional metamaterials such as fishnet metamaterials 15 , or by doping an ENZ medium with dielectric dopants [16][17][18][19][20] , or in all-dielectric metamaterials supporting a Dirac-like cone dispersion at the center of the Brillouin zone ("Comparison of Dirac-like cone-based zero index...." section) [21][22][23][24][25][26] . Dirac-like cone dispersion is formed by the accidental 3-fold degeneracy of two linear bands with conical dispersion and a quadratic dispersive band (which is flat near k = 0) at the center of the Brillouin zone.…”

On‐Chip Metasurface‐on‐Facets for Ultra‐High Transmission through Waveguides in Near‐Infrared

“…Exploiting photonic doping technique was suggested to achieve materials with near‐zero permittivity and tunable permeability. [ 34 ] Such a region behaves as a lumped reactive element that can be used to design impedance matching network suitable for operation in a wide range: from radio frequency (RF) to optical applications. Periodic subwavelength structures on waveguides can also be used to give the waveguide another functionality.…”

Abnormal Wave Propagation in Tilted Linear‐Crossing Metamaterials

“…This provides a new approach to achieving impedance matching of zero‐index media. [ 58 ] In addition, the TLCMM is intended for use in the design of new anisotropic optical cavities [ 59,60 ] and Moiré hyperbolic metasurfaces. [ 61 ] Our findings not only present a type of anisotropic metamaterial with special dispersion, but are also quite useful in a variety of applications related to planar integrated photonics, including directional propagation, cloaking, and filters.…”

“…Although the effective permittivity of a TLCMM is close to zero, our research results are based on use of a rotating optical axis instead of doping to achieve transmission without reflection. This provides a new approach to achieving impedance matching of zero-index media [58]. In addition, the TLCMM is intended for use in the design of new anisotropic optical cavities [59,60] and Moire ́ hyperbolic metasurfaces [61].…”