Analysis of optical nonlinearity by defect states in one-dimensional photonic crystals

Enhancement of optical nonlinearity in one-dimensional photonic-crystal structures with a defect is considered theoretically. It is shown that a large enhancement can be obtained for absorption saturation and degenerate four-wave mixing efficiency as a result of large optical field amplitude of the localized photonic-defect mode at the defect layer. The figure of merit of the use of the photonic-crystal structure is derived especially for systems in which the concentration of the nonlinear optical material can be arbitrarily adjusted. Optical bistability is also predicted for optically dense samples. They can be applied in real photonic devices because of their simple structure and the large enhancement obtained

High-Density β-FeSi2 crystals with 3D alignment fabricated by an oscillating magnetic field

9th International Symposium on Electromagnetic Processing of Materials (EPM2018)14–18 October 2018, Hyogo, JapanThis paper demonstrates three-dimensional alignment of ß-FcSi2 in sintered bulk specimens. The three-dimensional alignment was achieved by using an oscillating magnetic field during slip-casting under a magnetic field of 6T. Sintering using direct electric current heating was performed in various conditions. The degree of alignment did not significantly degrade during sintering process. Apparent density became as high as 97%. The degree of alignment tended to increase as grain size increased