%0 Journal Article
%T Homogeneous Hyperbolic Systems for Terahertz and Far-Infrared Frequencies
%A Leonid V. Alekseyev
%A Viktor A. Podolskiy
%A Evgenii E. Narimanov
%J Advances in OptoElectronics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/267564
%X We demonstrate that homogeneous naturally-occurring materials can form hyperbolic media, and can be used for nonmagnetic negative refractive index systems. We present specific realizations of the proposed approach for the THz and far-IR frequencies. The proposed structures operate away from resonance, thereby promising the capacity for low-loss devices. Following the initial proposal by Veselago in 1968 [1], negative refraction materials spent over 30 years as a forlorn curiosity before being resurrected with renewed interest from both theoretical and experimental groups. Within the last decade it was realized that these materials (known also as left-handed materials), along with a broader classes of exotic media (known as epsilon near-zero materials, hyperbolic materials, etc.) possess unusual properties, some of which were not recognized at the time of their conceptions [2]. These properties include resonant enhancement of evanescent fields, strong suppression of diffraction, unusual modification to optical density of states, potentially enabling near-perfect imaging below the diffraction limit, and leading to a new class of optical devices [3], as well as nontrivial behavior in the nonlinear regime [4]. Despite initial controversy over the realizability of negative index materials (NIMs), successful proof of principle demonstrations have been accomplished [3, 5¨C8]. Existing designs for left-handed materials rely on achieving overlapping dipolar and magnetic resonances in subwavelength composites (metamaterials) [9, 10], or using photonic crystals near the bandgap [3, 11]. Both of these approaches necessitate complicated 3D patterning of the medium with microstructured periodic arrays. Fabrication of such structures presents significant challenges even for GHz applications, while manufacturing metamaterials for higher frequencies becomes harder still [12]. Furthermore, near-resonant operational losses impose severe limitations on the imaging resolution [13]. As an alternative to periodic systems, a waveguide-based implementation of a NIM was proposed [14], which obviates the need for negative magnetic permeability and does not require periodic patterning. This approach circumvents major manufacturing obstacles to achieving NIM behavior at terahertz or optical frequencies, and simultaneously opens a new avenue in imaging, sensing, and light emission applications [15, 16] To achieve this behavior, the waveguide material must possess characteristics of a uniaxial medium with a significant anisotropy. Furthermore, this anisotropy must ensure that (the
%U http://www.hindawi.com/journals/aoe/2012/267564/