Two-Dimensional Ferroelectric Photonic Crystals: Optics and Band Structure

In this report we present an investigation of the optical properties and band structure calculations for the photonic structures based on the functional materials- ferroelectrics. A theoretical approach to the optical properties of the 2D and 3D photonic crystals which yields further insight in the phenomenon of the reflection from different families of lattice planes in relation to the presence of photonic gaps or photonic bands. We calculate the photonic bands and optical properties of LiNbO3 based photonic crystals. Calculations of reflection and transmission spectra show the features correspond to the onset of diffraction, as well as to additional reflectance structures at large values of the angle of incidence.Comment: 10 pages, 4 figures, 1 table, This paper were presented at 21 st International Symposium on Applications of Ferroelectrics (ISAF ECAPD PFM 2012 Averio, Portugal) and accepted for publication in Ferroelectrics (2013

Enhanced transmission of electromagnetic waves through split-ring resonator-shaped apertures

The design of aperture shape is a promising approach for enhanced transmission through a subwavelength aperture. We designed split-ring-resonator (SRR)-shaped apertures in order to increase the transmission through subwavelength apertures by making use of the strong localization of the electromagnetic field in SRR-shaped apertures. We obtained a promising result of 104-fold enhancement by utilizing SRR-shaped apertures. It is possible to use these proposed structures at optical frequencies by making several modifications such as decreasing the sharpness of edges and increasing the gap width. Since SRRs are already being realized at optical frequencies, our proposed SRR-shaped aperture structures are promising candidates for novel applications

Effects of Dielectric Substrate on Polarization Conversion Using Coupled Metasurfaces With and Without Tunneling

Dielectric substrates are technologically necessary components of various microwave and optical structures and devices, and may strongly affect their performance. For metasurfaces composed of subwavelength resonators, placing dielectric components in the proximity of resonators can lead to strong modification of subwavelength resonances and related transmission regimes. We focus on the effects exerted by material and geometrical parameters of such a dielectric substrate on linear‐to‐linear polarization conversion that appears in quasiplanar structures containing two coupled metasurfaces and enabling chirality. It is shown that spectral locations of the polarization conversion resonances and transmission efficiency at these resonances are strongly sensitive to the substrate parameters, whereas the ability of polarization conversion and related asymmetry of transmission can be preserved in wide ranges of parameter variation. The effects of a substrate are considered in detail for the mechanisms with and without tunneling, indicating a route to compact designs of quasiplanar structures for single‐ and multiband polarization conversion

Widely tunable resonant cavity enhanced detectors built around photonic crystals

We report a resonant cavity enhanced (RCE) detector built around a three-dimensional photonic band gap crystal. We have demonstrated the resonant cavity enhanced (RCE) effect by placing microwave detectors in defect structures built around dielectric and metallic based photonic crystals. We measured a power enhancement factor of 3450 for planar cavity structures built around dielectric based photonic crystals. The tuning bandwidth of the RCE detector extends from 10.5 to 12.8 GHz. We also demonstrated the RCE effect in cavities built around metallic structures. The power enhancement for the EM wave within these defect structures were measured to be around 190. These measurements show that detectors embedded inside photonic crystals can be used as frequency selective RCE detectors with increased sensitivity and efficiency when compared to conventional detectors