Radial Photonic Crystal for detection of frequency and position of radiation sources

Abstract

Based on the concepts of artificially microstructured materials, i.e. metamaterials, we present here the first practical realization of a radial wave crystal. This type of device was introduced as a theoretical proposal in the field of acoustics, and can be briefly defined as a structured medium with radial symmetry, where the constitutive parameters are invariant under radial geometrical translations. Our practical demonstration is realized in the electromagnetic microwave spectrum, because of the equivalence between the wave problems in both fields. A device has been designed, fabricated and experimentally characterized. It is able to perform beam shaping of punctual wave sources, and also to sense position and frequency of external radiators. Owing to the flexibility offered by the design concept, other possible applications are discussed.

A novel beam splitter based on graded photonic crystals

“…22 Radial PC is a type of GPC obtained by bending conventional PCs, and numerous types of radial PCs have been reported. [29][30][31][32][33] Oner et al 34 presented a new approach to achieve beam-bending via a graded radial PC with hyperbolic secant refractive index distribution. The superiority of the approach stems from the achievement of relatively compact and efficient waveguide turns.…”

Wireless energy transfer between anisotropic metamaterials shells

“…They have a cylindrical shape with a central void cavity. Among other purposes, valid also for their acoustic counterparts [10,11], RPC shells have been employed as high Q-factor resonant elements, position and frequency sensors or structures for beam-shaping [12,13]. These functionalities are a consequence of the anisotropy of the constitutive parameters.…”

Low-Qwhispering gallery modes in anisotropic metamaterial shells

“…The resonant modes associated with these anisotropic metamaterial shells allow designing devices for different types of applications, like beam shaping shells or position and frequency detectors. 11,14 In addition to the Fabry-Perot-like modes located in the RPC shell, cavity modes exist at the central cavity whose features are equivalent to those predicted for cylindrical cavities, 15 but now the localization is due to the band gap created by the RPC shell. Finally, whispering gallery modes (WGMs) are the third type of resonant modes existing in these structures and they are localized close to the interfaces at the inner and outer boundaries of the RPC shell with the background.…”

“…In particular, we focus on cylindrical shells based on radial photonic crystals (RPCs). 10,11 In comparison with the so called circular photonic crystals (CPCs), 12,13 the RPCs are multilayered structures that are invariant under radial translations and verify the Bloch's theorem. This last property is possible in cylindrical coordinates by using anisotropic and radially dependent constitutive parameters, which are feasible using the metamaterial concept.…”