Plasmon-induced near-infrared electrochromism based on transparent conducting nanoparticles: Approximate performance limits Appl. Phys. Lett. 101, 071903 (2012) Quantum mechanical study of plasmonic coupling in sodium nanoring dimers Appl. Phys. Lett. 101, 061906 (2012) Strong two-photon fluorescence enhanced jointly by dipolar and quadrupolar modes of a single plasmonic nanostructure Appl.High absorption efficiency is particularly desirable at present for various microtechnological applications including microbolometers, photodectors, coherent thermal emitters, and solar cells.Here we report the design, characterization, and experimental demonstration of an ultrathin, wide-angle, subwavelength high performance metamaterial absorber for optical frequencies.Experimental results show that an absorption peak of 88% is achieved at the wavelength of ϳ1.58 m, though theoretical results give near perfect absorption.

We show that the polarization states of electromagnetic waves can be manipulated through reflections by an anisotropic metamaterial plate, and all possible polarizations (circular, elliptic, and linear) are realizable via adjusting material parameters. In particular, a linearly polarized light converts its polarization completely to the cross direction after reflection under certain conditions. Microwave experiments were performed to successfully realize these ideas and results are in excellent agreement with numerical simulations. DOI: 10.1103/PhysRevLett.99.063908 PACS numbers: 42.25.Ja, 42.25.Bs, 78.20.Bh, 78.20.Fm Polarization is an important characteristics of electromagnetic (EM) waves. It is always desirable to have full control of the polarization states of EM waves. Conventional methods to manipulate polarization include using optical gratings, dichroic crystals, or employing the Brewster and birefringence effects, etc. [1,2]. Here we propose an alternative approach based on metamaterials [3][4][5][6]. Metamaterials have drawn much attention recently due to many fascinating properties discovered, such as the negative refraction [4], the in-phase reflection [5], and the axially frozen modes [6], etc. Here, we show that a specific metamaterial reflector can be employed to manipulate the polarization state of an incident EM wave. In particular, a complete conversion between two independent linear polarizations is realizable under certain conditions. We show the physics to be governed by the unique reflection properties of the metamaterial, and we perform experiments and finite-difference-time-domain (FDTD) simulations to demonstrate these ideas in the microwave regime.We start from studying a model system as shown in Fig. 1(a), which consists of an anisotropic homogeneous metamaterial layer (of a thickness d) with a dispersive relative permeability tensor $ 2 (with diagonal elements xx , yy , zz ) and a relative permittivity " 2 , put on top of a perfect metal substrate (with " 3 ! ÿ1, 3 1). We consider the reflection and refraction properties of the structure, when a monochromatic EM wave with a wave vectork in !=csincosx sinsinŷ cosẑ and a given polarization strikes on the surface. According to the Maxwell equations, EM waves should satisfyẼ2 k Ẽ inside the metamaterial layer withk the wave vector. Given k x and k y , the dispersion relation between ! and k z is determined by !=c 4 "ii ÿ1 jj k 2 l 0, where i; j; l x; y; z. The above equation has four roots corresponding to two refracted waves propagating forwardly and backwardly. The solution inside the second layer must be a linear combination of these four waves, manifesting the birefringence effect [1,7]. To match the boundary conditions, we must also expand the waves in other regions to linear combinations of four solutions, namely, the forward (backward) waves with s and p polarizations. The reflected beam thus generally consists of both s and p modes, even if the incident wave possesses one polarization. To solve these problems, we have extende...

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H-shaped resonators (inset) are adopted to realize, respectively, the desired B layer with negative ε and A layers with positive ε at the working frequencies [25]. (d) Top and middle panels: interference model and practical design of the metamaterial antireflection coating. Middle panel: experimentally measured reflectance and transmittance spectra for the normal incidence case. The solid and dashed lines represent the reflectance and transmittance of a bare GaAs surface [26]. (a) Figure 1 reprinted with permission from Martín-Moreno et al.,

A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The "super-reflection" device is realized by a ZIM with a perfect electric (magnetic) conductor inclusion of arbitrary shape and size for a transverse electric (magnetic) incident wave. In contrast, a ZIM with a perfect magnetic (electric) conductor inclusion for a transverse electric (magnetic) incident wave can be used to conceal objects of arbitrary shape. The underlying physics here is determined by the intrinsic properties of the ZIM.