Negative refraction and sub-wavelength focusing in the visible range using transparent metallo-dielectric stacks

Abstract

We numerically demonstrate negative refraction of the Poynting vector and sub-wavelength focusing in the visible part of the spectrum using a transparent multilayer, metallo-dielectric photonic band gap structure. Our results reveal that in the wavelength regime of interest evanescent waves are not transmitted by the structure, and that the main underlying physical mechanisms for sub-wavelength focusing are resonance tunneling, field localization, and propagation effects. These structures offer several advantages: tunability and high transmittance (50% or better) across the visible and near IR ranges; large object-image distances, with image planes located beyond the range where the evanescent waves have decayed. From a practical point of view, our findings point to a simpler way to fabricate a material that exhibits negative refraction and maintains high transparency across a broad wavelength range. Transparent metallo-dielectric stacks also provide an opportunity to expand the exploration of wave propagation phenomena in metals, both in the linear and nonlinear regimes.

Semiconductor-Metal-Semiconductor Core-Multishell Nanowires as Negative-Index Metamaterial in Visible Domain

“…Specifically, in the visible range, negative refraction has been demonstrated using metallic nanowires embedded in a dielectric matrix 3,4 , fishnet structures [5][6][7] , metaldielectric stacks/sandwiches [8][9][10] , planar waveguides 11 and metal-insulator-metal coaxial waveguides 12,13 . Despite the tremendous progress in the design and fabrication of NIM, developing high performance NIM without active loss compensation in the optical domain remains a challenge.…”

Reducing the losses of optical metamaterials

“…Such materials were carefully studied by different groups [51][52][53][54][55][56][57][58][59][60][61][62][63]. It is shown that indefinite media can have negative group refraction, backward-wave effect, and partial focusing.…”

“…But the double resonance scheme also causes large resonance losses and technical difficulties in design and fabrication. In addition to negative index materials, both theoretical and experimental studies show the properties of negative refraction and subwavelength imaging can also occur in some uniaxially anisotropic media, which can have lower losses and be easier to fabricate [51][52][53][54][55][56][57][58][59][60][61].…”

“…A lot of work has been done in anisotropic metamaterials, both experimentally [53,56] and theoretically [51,52,54,55,[57][58][59][60][61]. Liu and Zhang [61] derived the hyperbolic dispersion only theoretically in the Maxwell-Garnett approximation.…”

Application of Media with Negative Refraction Index to Electromagnetic Imaging. Fundamental Aspects.

“…This thesis has met many objections [Williams (2001)], which are not absolutely indisputable [Pendry (2001).]. Nevertheless, the concept of a superlens (in the form of a layer of medium with negative refraction), which was proposed in [Pendry (2000)] and allows one to completely overcome the diffraction limit in the ideal case, has found many supporters (see, for example, , Chen (2006), Alitalo (2007), , Scalora (2007), Podolskiy (2005)] and references therein). The superlens, as proposed by Pendry (2000), is a plane plate of material with negative refractive index.…”