A. de Baas

Bio: A. de Baas is an academic researcher. The author has contributed to research in topics: Metamaterial & Transformation optics. The author has an hindex of 1, co-authored 1 publications receiving 42 citations.

Metamaterials with extreme material parameters

Abstract: Metamaterials are characterized by their nonconventional material parameters, examples being media that possess very large or very small, even negative, permittivities and permeabilities. This article discusses a classification scheme in which various electromagnetic materials with extreme values of parameters (very large or very small) can be placed and related to one another.

Cloaking and invisibility: A review

Abstract: Invisibility has been a tantalizing concept for mankind over several centuries. With recent developments in metamaterial science and nanotechnology, the possibility of cloaking objects to incoming electromagnetic radiation has been escaping the realm of science fiction to become a technological reality. In this article, we review the state-of-the-art in the science of invisibility for electromagnetic waves, and examine the different available technical concepts and experimental investigations, focusing on the underlying physics and the basic scientific concepts. We discuss the available cloaking methods, including transformation optics, plasmonic and mantle cloaking, transmission-line networks, parallel-plate cloaking, anomalous resonance methods, hybrid methods and active schemes, and give our perspective on the subject and its future. We also draw a parallel with cloaking research for acoustic and elastodynamic waves, liquid waves, matter waves and thermal flux, demonstrating how ideas initiated in the field of electromagnetism have been able to open ground breaking venues in a variety of other scientific fields. Finally, applications of cloaking to non-invasive sensing are discussed and reviewed.

Gradient index metamaterials realized by drilling hole arrays

Abstract: Gradient index metamaterials have wide applications in the microwave and optical fields. Based on the quasi-static theory, such materials at the microwave band have been realized by drilling hole arrays on ordinary dielectric materials. As applications of the gradient index metamaterials, novel devices including a 45° dielectric wave-bending structure, a 16° wave-steering lens and a microwave focusing lens are designed and fabricated. Field mapping measurements validate the proposed gradient index metamaterials and the device designs. The method can be directly and easily extended to the design of cloaks, various lenses, beam shifters and beam-steering devices. It can also be applied in the optical band as long as quasi-static conditions are satisfied. The method and the devices may find applications in integrated circuit systems.

Experimental realization of a broadband bend structure using gradient index metamaterials

Abstract: Following the theoretical work on arbitrary waveguide bends using gradient-index and isotropic materials, a 90-degree bend structure is experimentally realized using artificial metamaterials. Broadband and low-loss unit cells, the I-shaped cells, are used in the laboratory prototype. Field mapping measurement validates the design. The method can be directly and easily extended to the design of directional cloaks, microwave lens, beam shifters, and beam-steering devices.

Controlling light with plasmonic multilayers

Abstract: Recent years have seen a new wave of interest in layered media – namely, plasmonic multilayers – in several emerging applications ranging from transparent metals to hyperbolic metamaterials. In this paper, we review the optical properties of such subwavelength metal–dielectric multilayered metamaterials and describe their use for light manipulation at the nanoscale. While demonstrating the recently emphasized hallmark effect of hyperbolic dispersion, we put special emphasis to the comparison between multilayered hyperbolic metamaterials and more broadly defined plasmonic-multilayer metamaterials A number of fundamental electromagnetic effects unique to the latter are identified and demonstrated. Examples include the evolution of isofrequency contour shape from elliptical to hyperbolic, all-angle negative refraction, and nonlocality-induced optical birefringence. Analysis of the underlying physical causes, which are spatial dispersion and optical nonlocality, is also reviewed. These recent results are extremely promising for a number of applications ranging from nanolithography to optical cloaking.