Single-layer terahertz metamaterials with bulk optical constants

Abstract

We investigate the conditions under which single layer metamaterials may be described by bulk optical constants. Terahertz time domain spectroscopy is utilized to investigate two types of geometries, both with two different sizes of embedding dielectric -cubic and tetragonal unit cells. The tetragonal metamaterials are shown to yield layer dependent optical constants, whereas the cubic metamaterials yielded layer independent optical constants. We establish guidelines for when ǫ and µ can be used as material parameters for single layer metamaterials. Experimental results at terahertz frequencies are presented and supported by full wave three dimensional electromagnetic simulations.

Interferometric description of optical metamaterials

“…So far, both numerical [2][3][4][5] and experimental [6][7][8][9] techniques have been used to obtain the transmission and reflection coefficients for metamaterial slabs with a rather limited number of nanostructured layers. The coefficients obtained for such slabs do not necessarily describe the properties of a bulk metamaterial.…”

“…The coefficients obtained for such slabs do not necessarily describe the properties of a bulk metamaterial. One approach to characterize the material would be to successively increase the number of layers and see if the optical characteristics converge [3,4,9]. However, the understanding of the real physics that determines the final transmission properties is lost when using this procedure.…”

Simultaneous existence of the zero- n ¯ and zero-ϕeff gaps in metamaterial-polaritonic photonic superlattices

“…However, we have observed that the zero-n gap edges can only be described in superlattices composed by alternating layers of LHM and a conventional dielectric [4], but this approximation does not remain valid for superlattices composed by two alternating dispersive media. According with recent advances in microstructuring material techniques and with the possibility to develop single-layer terahertz metamaterials [8], we expect that present results may be useful for applications in filters and reflectors.…”

“…Therefore, the possibility to have the simultaneous existence of the zero-n and the zero-φ eff gaps in the same structure, operating at terahertz range, becomes of great importance for a wide range of applications, such as omnireflectors and optical filters. In fact, in the last two years, single-layer terahertz metamaterials were fabricated by means of the optical lithography technique [8], opening up the possibility to realize these metamaterial-polaritonic photonic superlattices with optical responses in the THz range.…”

Simultaneous omnidirectional zero-n¯ and zero-ϕ_eff non-Bragg gaps in metamaterial-polaritonic photonic superlattices

“…These studies were motivated by the new possibilities to manipulate the light propagation properties, opening routes for the design and development of new optical devices [15][16][17]. On the other hand, the advent of metamaterials [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], which were first idealized by Veselago [18] as materials with simultaneous negative permittivity ε and negative permeability μ and, hence, a negative index of refraction n ε p μ p , has opened the possibility to obtain several new phenomena, such as the existence of the non-Bragg gaps, i.e., gaps with a physical origin completely different from the conventional Bragg scattering mechanism, which cannot be observed in superlattices composed by double positive (DPS) or conventional dielectric materials. In present days, there are several kinds of metamaterials which are commonly known as single negative electric (SNE), single negative magnetic (SNM), and double negative (DNG) metamaterials according to the signs of their electric and magnetic effective responses, respectively.…”