Left-Handed Materials in Microwave and Infrared Frequencies

Left-handed or negative index metamaterials, i.e. composite materials with electrical permittivity, magnetic permeability and refractive index negative over a common frequency range, have been a subject of extremely increased attention in the last seven years. This is due to the many novel and unusual properties of those materials (like opposite phase and group velocities, negative refraction, etc) which entail unique capabilities in the manipulation of electromagnetic waves. Such capabilities are subwavelength resolution imaging, cloaking, miniaturization and optimization of microwave components and systems (like, e.g., antennas and waveguides) and many more. In the present talk we will introduce the main concepts related with the left-handed materials, along with the main capabilities of those materials. Moreover, we will present the attempts of our group to realize, analyze and optimize various left-handed material designs. The main designs investigated are combinations of split-ring resonators (SRRs) (metallic rings with gaps - providing negative permeability) and continuous wires (providing negative permittivity), as well as combinations of metallic parallel-plate-pairs and continuous wires (see Fig. 1). Particular attention will be given in the study of the electromagnetic response of the SRRs and the influence of this response to the electromagnetic behavior of an SRRs&wires system, as well to the understanding of the SRRs behavior in the infrared and optical range.