High-Order Angle and Polarization Resolved Reflection of Artificial Opal Photonic Crystal

We present angle resolved reflection measurements showing the polarization dependence of photonic band gap in artificial opal photonic crystals. The SiO2 opals were prepared using thermal-assisted cell method. The observation of well-defined diffraction pattern indicates the samples with high quality. The reflection measurements were analyzed in the high energy region up to a/l = 1.6. It is shown that the diffraction peaks depend on s- and p-polarized light illumination. The polarization anisotropy effect due to symmetric properties of opal structure. The experiment results agree fairly well with calculated photonic band structure and are also discussed with predictions based on group theory. Angular reflection has implications in polarized light scattering in plasmonic structures and metamaterials and is also useful in applications like nano scale polarization splitters and lasers.

Wave absorption control in the new designed photonic metamaterials with artificial opal

Photonic metamaterials consisting of artificial opal with magnetic inclusions were considered, used in controllable microwave electronic devices. The analyzed structures consist of matrices of SiO2 nanospheres (diameter 200 - 400 nm) with included clusters of ferrite spinels (MnxCo0.6-xZn0.4Fe2O4, NixCo0.6-xZn0.4Fe2O4, LaxCo0.6-xZn0.4Fe2O4, NdxCo0.6-xZn0.4Fe2O4) in interspherical nanospacing (4 ÷ 7% concentration). The ellipsoidal clusters are polycrystalline, with spatial dimensions of 20 – 30 nm and grains of 5 – 12 nm. A controlled wave absorption was obtained in these high inductivity structures. Evolution of the wave attenuation coefficient, α[dB/m], in function of the applied magnetic field and particle inclusion size, for different content of the magnetic ions in the ferrite inclusion, have been determined at frequencies around the samples ferromagnetic resonance, by structural simulation. The test configuration was: sample inside the rectangular waveguide, mode TE10, in the frequency range 24 ÷ 40 GHz. The polarizing magnetic field for the ferrites was tested in the range of 0 ÷ 20 kOe and minimized by modifying the structure. The metamaterial design optimization was realized, controllable by different parameters at structure level. The ferromagnetic resonance influence on the control process was pointed out and also the particular results and effects which can be induced by the resonant behavior.

Artificial opal photonic crystals and inverse opal structures – fundamentals and applications from optics to energy storage

This review outlines the fundamentals and applications of artificial opal photonic crystals, their fabrication, development and adaption from optics to energy storage research.