Rectifying Nonreciprocal Perfect Absorber Based on Generalized Effective-Medium Theory for Composite Magnetic Metamaterials

Abstract

In this work, we demonstrate the implementation of a nonreciprocal perfect absorber (NPA) made of composite magnetic metamaterials (MMs) consisting of an array of dielectric core loaded (DCL) ferrite rods with either hollow or dielectric cores. The NPA can be functionalized as a PA for the incident beam at a specified direction, while at the symmetric direction the absorption is very weak so that a strong reflection is observed due to the excitation of nonreciprocal magnetic surface plasmon. Interestingly, it is shown that the material loss might be beneficial to the absorption, but it will result in the degradation of nonreciprocal performance. For the delicately designed MMs, only a very small material loss is necessary and simultaneously ensures the high nonreciprocal performance of NPA. To interpret the high quality of NPA, we developed a generalized effective-medium theory for the composite MMs, which shows the direct consequence of the DCL ferrite rods with optimized core size and core permittivity. The partial wave analysis indicates that the nonreciprocal dipole resonance in DCL ferrite rod plays a crucial role in improving the nonreciprocity. The narrow band feature and the angular sensitivity make the NPA promising for the diode-like functionalities. In addition, by controlling the magnitude and orientation of bias magnetic field both the operating frequency and the nonreciprocity can be flexibly controlled, adding an additional degree of freedom. The concept proposed in this research is promising for microwave photonics and integrated photonics.

Narrow-band and highly absorbing fano resonance in a cavity-coupled dielectric metasurface

“…Based on resonance-enhanced light-matter interaction, metamaterials have become a promising platform for developing non-invasive and sensitive biosensors [4,5]. In addition, by breaking the time-reversal symmetry with a magnetic field, novel nonreciprocal properties such as unidirectional light absorption and scattering have been reported in magnetic metamaterials, which have added new degrees of freedom for light manipulation [6][7][8].…”

The diversity of isofrequency surface topologies in a hypercrystal composed of ferrite- and semiconductor-based metamaterials

“…Furthermore, the occurrence of Dirac-like singularities on the isofrequency surface of lossless epsilon-near-zero and/or mu-near-zero metamaterials, which is analogous to an effective zero optical mass, has generated significant interest. In such systems, phenomena such as giant optical non-locality, conical refraction, or unique surface states can be observed 26 – 31 .…”