Transformation optics is a powerful tool to design various novel devices, such as invisibility cloak. Fantastic effects from this technique are usually accompanied with singular mappings, resulting in challenging implementations and narrow bands of working frequencies. Here article, we find that Fabry-P\'erot resonances can be used transformation optical devices not only easy realize but also work well for set resonant frequencies (multiple frequencies). As an example, fabricate prototype...

Absorption of microwaves by metallic conductors is typically inefficient, albeit naturally broadband, due to the huge impedance mismatch between metal and free space. Reducing ultrathin profile may improve absorption efficiency, but a maximal 50% limit induced field continuity exists. Here, we experimentally show that perfect (100%) can be realized in single layer conductive film when illuminated coherently two oppositely directed incident beams. Our experiments keep simultaneously break...

The maximal absorption rate of ultrathin films is 50% under the condition that tangential electric (or magnetic) field almost constant across film in a symmetrical environment. However, with certain reflectors, can be greatly increased, even to perfect (100%). In this paper, we explicitly derive general conditions absorptive parameters achieve types reflectors film. We find classified into three groups, exhibiting (1) large permittivity (permeability), (2) near-zero permeability...

Abstract We have experimentally and numerically demonstrated that the coherent perfect absorption (CPA) can equivalently be accomplished under single beam illumination. Instead of using counter-propagating dual beams, we introduce a magnetic conductor (PMC) surface as mirror boundary to CPA configuration. Such PMC practically embodied, utilizing high impedance surfaces, i.e., mushroom structures. By covering them with an ultrathin conductive film sheet resistance 377 Ω, (100%) microwave is...

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We experimentally demonstrate that perfect electromagnetic absorption can be realized in the one-atom thick graphene. Employing coherent illumination waveguide system, absorbance of unpatterned graphene monolayer is observed to greater than 94% over microwave X-band, 7–13 GHz, and achieve a full absorption, >99% experiment, at ∼8.3 GHz. In addition, characteristic manifests equivalently wide range incident angle. The experimental results agree very well with theoretical calculations....

We study the absorption properties of ultrathin conductive films in microwave regime, and find a moderate effect which gives rise to maximal absorbance 50% if sheet (square) resistance film meets an impedance matching condition. The exhibits frequency-independent feature takes place on extremely subwavelength scale, thickness. As realistic instance, ∼5 nm thick Au is predicted achieve optimal absorption. In addition, methodology based metallic mesh structure proposed design absorbers....

Abstract In this work, we demonstrate an one-dimensional cloak consisting of parallel-plated waveguide with two slabs gradient index metamaterials attached to its metallic walls. it objects are hidden without limitation polarizations and good performance is observed for a broadband frequencies. The experiments at microwave frequencies carried out, supporting the theoretical results very well. essential principle behind proposed cloaking device based on mode conversion, which provides new...

Abstract Fano resonances – resonant scattering features with a characteristic asymmetric profile have generated much interest, due to their extensive and valuable applications in chemical or biological sensors, new types of optical switches, lasers nonlinear optics. They been observed wide variety systems, including photonic crystals, metamaterials, metallic gratings nanostructures. In this work, waveguide structure is designed by employing gradient-index supporting strong extremely sharp...

In this Letter, we study the transmission response of microwaves through two identical metallic plates machined with ultranarrow slit arrays. The measured and calculated spectra consistently display a striking peak at wavelength much larger than any characteristic length structure (e.g., about twenty-fold lattice period), which can not be directly explained by existing mechanisms. Both LC-circuit-based microscopic picture effective-medium-based macroscopic model are established to capture...

According to the theory, an ultrathin conductive film can achromatically dissipate electromagnetic waves with frequency ranging from radio terahertz. A moderate absorption effect, which gives rise a maximal absorbance of 50%, be found if impedance matching condition is satisfied. We have experimentally demonstrated frequency-irrelevant, by employing nanofilm and launching terahertz at Brewster angle when sheet (square) resistance meets condition. In entire spectral range covered our...

We present a simple approach to measure the dielectric constant of solid materials. In this approach, powder for under investigation is mixed with oil at specific volume fraction. By measuring and mixture, permittivity inclusion, i.e. solid, can be accurately derived from Maxwell-Garnett effective medium theory. With method, strict requirements shape surface flatness in conventional configurations waved off, meanwhile broadband obtained. The demonstrations on alumina glucose show valid robust.

Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model realize metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in low-ε insulating oil, structured exhibits liquid-like properties from dispersing as well isotropic negative parameters caused by Mie resonances dispersed microspheres. The work presented here will benefit development fluids toward metamaterials.

Spatially mapping electromagnetic fields in the quasi-two-dimensional field mapper (a parallel plate waveguiding system; Justice et al. (2006)) for characterizing metamaterial devices, especially those integrating metal boundary, may encounter troubles including leakage caused by air gap and energy guiding along finitely high walls. To eradicate them, a moving contact approach is proposed. The physical between mobile walls stationary upper of closed, while their relative movement still...

We have investigated the photonic Wannier-Stark ladder in system of coupled electromagnetic cavities, which consists a stack metallic plates structured with subwavelength apertures and where tilted potential effect is mimicked by imposing gradient variation refractive index. Making an analogy to its quantum counterpart assuming translational property solutions, we shown has eigenenergies, that is, frequencies, geometrical series. Within approximation small gradient, states manifest...

We propose a two-dimensional numerical model based on finite element method to simulate the front electrode design with considering full complexity of electrode, which has been testified by comparing simulation experiment.

We experimentally demonstrate optical theorem can be employed to obtain the scattering cross-section (SCS) for transformation media. Different from total scattering-field integration approach, method is a transmission-like measurement SCS characterization, and furthermore facilitates accessing broadband spectrum bandwidth evaluation. In order examine this method, we measure of field concentrator, which medium with multiple working frequencies [15], at microwave 2-18 GHz, make comparison...

We study the transmission response of microwaves through two identical metallic plates perforated with periodical ultranarrow slits. The experimental and numerical spectra consistently display a striking peak at wavelength much larger than any characteristic length microstructure (e.g., about 20-fold lattice constant), which can not be directly interpreted by existing mechanisms. Both LC-circuit-based microscopic picture effective-medium-based macroscopic model are established to capture...