Metasurfaces for full control over reflection and transmission

We investigate how to ensure full control over fields, reflected from and transmitted through an electrically thin layers (sheets). To achieve this goal we use single periodic arrays of small particles. In this study, we demand the layer to exhibit different properties (i.e., different phases and amplitudes of refection and transmission coefficients) for waves incident from different sides of the array plane. We have shown that the only possibility to get such functionality in one single layer of particles is to use particles with bi-anisotropic coupling. We have found that using this concept, full control over the reflection/transmission functionalities of the layer, independently for different sides of the layer, is possible. For such a layer different kinds of functionalities can be defined, such as required transmissivities or required reflection/transmission phases, as needed for various applications.

• One-way absorber layers: Suppose you need a layer which absorbs incident electromagnetic wave from one side of the layer showing different properties for the wave coming from the other side. An isolator layer is one of the most interesting applications of this special case. More information about this class of layers can be found in our recently published paper (Y. Ra'di, V. S. Asadchy, and S. A. Tretyakov, "Total absorption of electromagnetic waves in ultimately thin layers," IEEE Trans. Antennas Propag., vol. 61, no. 9, pp. 4606-4614, 2013).

• One-way transparent layers: Layers which are transparent for the wave hitting one side of the layer but have some controllable properties for the waves coming from the other side, has also been subject of one of our recent studies (Y. Ra'di, V. S. Asadchy, and S. A. Tretyakov, "One-way transparent sheets," Y. Ra'di, V.S. Asadchy, and S.A. Tretyakov, One-way transparent sheets, Physical Review B, vol. 89, p. 075109, 2014.

• Metamirrors: In our definition, metamirrors are layers which fully reflect coming electromagnetic waves from different sides of the layer with different phases. Currently, we are developing metamirrors with different non-uniform phase distributions on each side of the layer. As a special case, one can possibly realize a layer which focuses plane waves incident from one side but works as perfect magnetic conductor from the other side. (Y. Ra'di, V. S. Asadchy, S. A. Tretyakov, Tailoring reflections from thin composite metamirrors, IEEE Trans. Antennas Propag., 2014.)