A. V. Baryshev

Contribution of the surface plasmon resonance to optical and magneto-optical properties of a Bi:YIG-Au nanostructure

We have studied the optical and magneto-optical properties of bismuth-substituted yttrium iron garnet (Bi:YIG) films with Au nanoparticles dispersed on their top surfaces. These structures exhibit surface plasmon resonances due to light coupling to Au nanoparticles, showing, for any direction of polarization of the incoming light beam, an absorption band in the spectral range of 500–750nm. For transmitted light beams with the plasmon-resonant wavelengths, the plane of polarization rotates slightly when the structure is not magnetized. Polarization-resolved transmission spectra show that this rotation is due to anisotropy of light propagation through the array of Au nanoparticles. For the structure comprising the 90-nm-thick Bi:YIG film and the array of Au nanoparticles of several tens of nanometers, the Faraday rotation angle enhances as compared with that for the original Bi:YIG film of the same thickness.

Three-dimensional magnetophotonic crystals based on artificial opals

We fabricated and experimentally investigated three-dimensional magnetophotonic crystals (3D MPCs) based on artificial opals. Opal samples with three-dimensional dielectric lattices were impregnated with different types of magnetic material. Magnetic and structural properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. We have shown that magnetic materials synthesized in voids of opal lattices and the composites obtained have typical magnetic properties.

Efficiency of optical sensing by a plasmonic photonic-crystal slab

A one-dimensional photonic crystal with termination by a noble metal film?a plasmonic photonic-crystal slab?is theoretically analysed for its optical response at the variation of the dielectric permittivity of an analyte. A sharp attenuation peak associated with a ?noble metal-visualized? Bloch surface wave is observed due to plasmon absorption in the metal. We investigate the sensing performance of the slab and show that it is tolerant to the variation of probing conditions and the slabs structural parameters. As a consequence, the considered sensor exhibits an enhanced sensitivity and good robustness in comparison with conventional surface-plasmon and Bloch surface wave sensors.

Magneto-optical properties of three-dimensional magnetophotonic crystals

Properties of three-dimensional magneto-photonic crystals based on artificial opals were studied by optical spectroscopy. We have investigated an influence of magnetic materials embedded into opal lattice on optical and magnetic properties of synthesized composites. It was shown that increase of volume fraction of magnetic material in opal lattice leads to decrease of transmissivity of synthesized composites. We measured Faraday rotation of opal-magnetite composites and found considerable changes in the Faraday rotation inside the (111) photonic bandgap.

Frontiers in Magneto-optics of Magnetophotonic Crystals

The recently published and new results on design and fabrication of magnetophotonic crystals of different dimensionality are surveyed. Coupling of polarized light to 3D photonic crystals based on synthetic opals was studied in the case of low dielectric contrast. Transmissivity of opals was demonstrated to strongly depend on the propagation direction of light and its polarization. It was shown that in a vicinity of the frequency of a single Bragg resonance in a 3D photonic crystal the incident linearly polarized light excites inside the crystal the TE- and TM-eigen modes which passing through the crystal is influenced by Bragg diffraction of electromagnetic field from different (hkl) sets of crystallographic planes. We also measured the Faraday effect of opals immersed in a magneto-optically active liquid. It was shown that the behavior of the Faraday rotation spectrum of the system of the opal sample and magneto-optically active liquid directly interrelates with transmittance anisotropy of the opal sample. The photonic band structure, transmittance and Faraday rotation of the light in three-dimensional magnetophotonic crystals of simple cubic and face centered cubic lattices formed from magneto-optically active spheres where studied by the layer Korringa-Kohn-Rostoker method. We found that a photonic band structure is most significantly altered by the magneto-optical activity of spheres for the high-symmetry directions where the degeneracies between TE and TM polarized modes for the corresponding non-magnetic photonic crystals exist. The significant enhancement of the Faraday rotation appears for these directions in the proximity of the band edges, because of the slowing down of the light. New approaches for one-dimensional magnetophotonic crystals fabrication optimized for the magneto-optical Faraday effect enhancement are proposed and realized. One-dimensional magnetophotonic crystals utilizing the second and the third photonic band gaps optimized for the Faraday effect enhancement have been successfully fabricated. Additionally, magnetophotonic crystals consist of a stack of ferrimagnetic Bi-substituted yttrium-iron garnet layers alternated with dielectric silicon oxide layers of the same optical thickness. High refractive index difference provides the strong spatial localization of the electromagnetic field with the wavelength corresponding to the long-wavelength edge of the photonic band gap.

Synthesis of ferrite on SiO2 spheres for three-dimensional magneto-photonic crystals

This article reports the preparation of submicrometric magnetic particles which are promising parts for fabrication of three-dimensional magneto-photonic crystals. In our experiments SiO2 spheres with diameter of about 260 nm were coated with Fe3O4 fine particles from an aqueous solution at room temperature. It is found that spheres coated with Fe3O4 fine particles with a diameter of about 20 nm are synthesized when the ratio of Fe3+/Fe2+ is in the range 50%–100% and the pH value is in the range 8–10.

Magnetic field sensors using magnetophotonic crystals

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.

Peculiarities of plasmon-modified magneto-optical response of gold–garnet structures

Responses of plasmonic magneto-optical (MO) (gold–garnet) systems in different regimes of light propagation to identify the features of plasmon-modified MO responses are demonstrated. The absorption band associated with excitation of the localized plasmon resonance in gold is shown to influence a cumulative angle of polarization rotation of the considered systems. The resonance is responsible for enhanced polarization rotation when gold–garnet systems are magnetized; however, this enhancement is found to be the reciprocal effect, with no influence on the inherent properties of garnet from the near field. The experimental results are in good agreement with the numerical analysis results.

Magnetophotonic Crystals: Experimental Realization and Applications

The most striking feature of photonic crystals, compared with homogeneous optical materials, is the existence of photonic band gaps. The band gaps are responsible for resonant light coupling to constituents of photonic crystals in both the cases where periodicity is ideal or broken by defects introduced intentionally. What if photonic crystals are made of magnetic materials? May magnetism bring about new advances in the field of photonic crystals where not only amplitudes but also polarization states are controlled by the spin subsystem? Below we will discuss magnetophotonic crystals and show that light confinement in their non-reciprocal magnetic constituents results in new magneto-optical phenomena. This chapter reviews studies on magnetophotonic crystals with various designs; it focuses on their experimental realizations, theoretical analysis and application to spatial light modulators.

Resonant surface magnetoplasmons in two-dimensional magnetoplasmonic crystals excited in Faraday configuration

The resonant excitation of surface magnetoplasmons in Faraday configuration is studied via spectroscopy of the longitudinal magneto-optical Kerr effect (LKE) in two-dimensional nickel-based magnetoplasmonic crystals. The fulfillment of phase matching conditions for surface plasmon-polaritons using both reciprocal vectors of the magnetoplasmonic crystal allows tuning of the LKE enhancement in the wide spectral range.