We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garnet (Au-Bi:YIG) composite films in which Au particles are embedded into Bi:YIG in two different ways. First type were samples in which planar arrays of Au particles were introduced into the middle of Bi:YIG films using a step-by-step sputtering technique. Second type were granular films fabricated using simultaneous co-sputtering of Au and Bi:YIG; in these films Au particles occupy positions inside composite films in a random way. Absorption bands associated with localized surface plasmon resonances (LSPRs) were observed in transmission spectra of films of both types. In the spectral range of LSPRs, samples of Au-array type exhibited larger Faraday rotation angles as compared with that for reference Bi:YIG films of the same thickness. However, given that the volume fraction of Au particles was nearly the same for both types, the
enhancement of Faraday rotation for samples of Au-granular type was insignificantly altered. Experiments showed that of the primary importance is the role of the interfaces between Au particles and Bi:YIG. Theoretical estimations showed that, in samples of
Au-granular type, air shells appeared between Au particles and Bi:YIG during fabrication. In fact, annealing needed for crystallization of Bi:YIG films is always accompanied with an expansion of their thicknesses.
In this work, we investigated the possibility of application of magnetophotonic crystals to the optical magnetic field
sensor. The structure of 1D-MPC was (Ta2O5/SiO2)5/Bi:YIG/ (Ta2O5/SiO2)5 (magnetic material as a defect layer between
two Bragg reflectors) on a fused quarts substrate using RF magnetron sputtering apparatus. We used Bismuth substituted
yttrium iron garnet (Bi:YIG) polycrystal film as a defect layer, because Bi:YIG is well known as the magnetic material
with effective MO properties, even if it is polycrystal. Due to specially designed structure, the localized mode appeared
at the wavelength of 880 nm, which is tunable by the thickness of multi layers or defect layer. At the wavelength of
localized mode, Faraday rotation was shown large enhancement of 1.5°, that is fifty times larger than for single Bi:YIG
polycrystal film of the same thickness.
Highly transparent polycrystalline lanthanum-modified lead zirconate titanate (PLZT) thick films were prepared using
aerosol deposition method (ADM) of calcined complex powders. Effects of incident angle of aerosol and particle size as
well as annealing temperature on optical and electro-optic properties of films were investigated. The film with higher
transparency was obtained with smaller particle, because the aggregation frequency of particles in aerosol decreased with
reducing the particle size. The transparency of the films increased with decreasing the incident angle of aerosol. This is
presumably due to the fact that the optimal incident angle of aerosol results in the reduction of impurity and pore, which
makes the film to be denser micro-structurally. The XRD peaks of as-deposed films shifted to lower angle side,
indicating that large compressive stress, which was generated by mechanical collision of particles, acted in the films. But
the stress was eliminated through annealing process. The birefringence change in annealed film increased exponentially
with an applied electrical field to reach 0.0036 at 100kV/cm. To make a multimode waveguide, the PLZT film with 22
μm thick was formed into a silicon groove, which was fabricated through anisotropic wet etching process. The far field
profile of multimode optical wave transmitted through the fabricated PLZT waveguide was successfully observed and
could be controlled with an applied electrical field.
We demonstrated a magneto-optic spatial light modulator with one-step pattern formation of iron-garnet films on ion-milled substrates by LPE. The one-step pixel growth is based on the combination of a single-crystal epitaxial film growth (pixel area) by LPE and a impeded film growth (pixel gap area) on a substrate whose surface has been locally damaged and milled by ion bombardment before film deposition. This method overcomes the disadvantages associated with groove etching of the conventional MOSLM. The fabricated prototype MOSLM is switched by applying driving currents of 40 mA for the bottom conductor line and 80 mA for the top conductor line under external bias field of 20 Oe, which is over 2 times smaller than that of the conventional MOSLM. These results strongly suggest that the novel MOSLM can provide higher resolution, simpler fabrication process, more compact systems and lower driving current. Also, the selective-area LPE method offers new possibilities for the fabrication of integrated magneto-optic light switch arrays, magnetic waveguides and similar devices.
This work was aimed at fabrication of a three-dimensional magento-photonic crystal. In our experiments LATEX spheres with diameter of about 200 nm were coated with Fe3O4 fine particle. The diameter of Fe3O4 fine particles is about 30 nm when ration of Fe3+ / Fe2+ (r) = 3% and pH = 8.6. The diameter of these particles decreases about 10 nm by increasing up to r=20% in the same pH region. It was found that a decrease of the coated particles size can be made as low as the size of 5% of LATEX spheres diameter. Therefore, it may use these particles for preparation a three-dimensional magento-dielectric structure.
We demonstrated a flat-surface magneto-optic spatial light modulator (MOSLM) without physically isolated pixels and an external bias coil. The flat-surface MOSLM, which was fabricated by a simple process, was designed as a compact system with a high resolution and very low driving current. Flat-surface pixels for the novel MOSLM were magnetically isolated and produced by the combinatory use of the local annealing effect that reduced magnetization 4πMs of pixel areas and the stress effect that produced sharp variations of magnetic anisotropy in a magnetic garnet film under the edge of a metal layer. The novel MOSLM can provide a higher resolution, a simpler fabrication process, more compact systems and a lower driving current than the conventional MOSLM.