Yu. S. Dadoenkova

Photonic-magnonic crystals: Multifunctional periodic structures for magnonic and photonic applications

We investigate the properties of a photonic-magnonic crystal, a complex multifunctional one-dimensional structure with magnonic and photonic band gaps in the GHz and PHz frequency ranges for spin waves and light, respectively. The system consists of periodically distributed dielectric magnetic slabs of yttrium iron garnet and nonmagnetic spacers with an internal structure of alternating TiO2 and SiO2 layers which form finite-size dielectric photonic crystals. We show that the spin-wave coupling between the magnetic layers, and thus the formation of the magnonic band structure, necessitates a nonzero in-plane component of the spin-wave wave vector. A more complex structure perceived by light is evidenced by the photonic miniband structure and the transmission spectra in which we have observed transmission peaks related to the repetition of the magnetic slabs in the frequency ranges corresponding to the photonic band gaps of the TiO2/SiO2 stack. Moreover, we show that these modes split to very high sharp (a...

Light reflection from nonlinear optical dielectric film on a bigyrotropic magnetoelectric substrate at angles close to Brewster angles

Light reflection from the interface of a dielectric film, characterized by a cubic optical nonlinearity, on a bigyrotropic substrate magnetoelectric substrate is investigated theoretically. Relations are obtained for the reflection coefficient as a function of the incidence angle of the light for the main magneto-optic configurations: polar, longitudinal, and transverse. The effect of the magneto-electric and magneto-optical contributions to the electric polarization of such a biaxial structure on the polarization state of the light reflected at angles close to the Brewster angles is studied.

Controlling the Goos-Hänchen shift with external electric and magnetic fields in an electro-optic/magneto-electric heterostructure

We present a theoretical investigation of the Goos-Hanchen effect upon light reflection from a heterostructure consisting of an electro-optic film deposited on a magneto-electric film grown on a nonmagnetic dielectric substrate. It is shown that the linear magneto-electric interaction leads to an increase of the lateral shift even in the absence of any applied electric field. The presence of the electro-optic layer enables the control of the Goos-Hanchen shift and of the position of its maximum (with respect to the angle of incidence) through a variation of the magnitude and orientation of an applied electric field. It is also demonstrated that applying an external magnetic field in order to reverse the magnetization in the magnetic layer results (under the influence of the magneto-electric interaction in the system) in a sign reversal of the lateral shift but a nonreciprocal change of its amplitude.

Four-layer nanocomposite structure as an effective optical waveguide switcher for near-IR regime

We present a theoretical study of the dispersion and energy properties of the eigenwaves (TE- and TM- modes) in a four-layer structure composed of a magneto-optical yttrium iron garnet guiding layer on a dielectric substrate covered by a planar nanocomposite guiding multilayer. The bigyrotropic properties of yttrium-iron garnet are taken into account for obtaining the dispersion equation and an original algorithm for the guided modes identification is proposed. We demonstrated the polarization switching of TE- and TM-modes dependent on the geometrical parameters of the guiding layers. The dispersion diagrams and field profiles are used to illustrate the change of propagation properties with variation of the multilayer thickness ratio of the nanocomposite layers. The energy flux distributions across the structure are calculated and the conditions of the optimal guiding regime are obtained. The power switching ratio in the waveguide layers of about 6 dB for the wavelength range of 100 nm is shown to be achieved.

Tunnelling of frequency-modulated wavepackets in photonic crystals with amplification

The tunnelling of a long-time (about 100 μs) frequency-modulated electromagnetic pulse through a one-dimensional active dielectric photonic crystal and the influence of the frequency modulation of the wavepacket on its time delay and peak velocity is theoretically investigated. The possibility of tuning the characteristics of the transmitted pulse using frequency modulation is demonstrated.

Confined states in photonic-magnonic crystals with complex unit cell

We have investigated multifunctional periodic structures in which electromagnetic waves and spin waves can be confined in the same areas. Such simultaneous localization of both sorts of excitations can potentially enhance the interaction between electromagnetic waves and spin waves. The system we considered has a form of one dimensional photonic-magnonic crystal with two types of magnetic layers (thicker and thinner ones) separated by sections of the dielectric photonic crystals. We focused on the electromagnetic defect modes localized in the magnetic layers (areas where spin waves can be excited) and decaying in the sections of conventional (nonmagnetic) photonic crystals. We showed how the change of relative thickness of two types of the magnetic layers can influence on the spectrum of spin waves and electromagnetic defect modes, both localized in magnetic parts of the system.

Transverse magneto-optic Kerr effect and Imbert–Fedorov shift upon light reflection from a magnetic/non-magnetic bilayer: impact of misfit strain

We present a theoretical study of the influence of the misfit strain on the transverse magnetooptic Kerr effect (TMOKE) and the transverse shift (Imbert–Fedorov effect) experienced by a light beam reflected from the surface of a magnetic/non-magnetic bilayer. The bilayer consists of a magnetic, gyrotropic yttrium-iron garnet film epitaxially grown on a non-magnetic dielectric gadolinium-gallium garnet slab. We use Green’s function method to calculate the reflection matrix in the presence of strain. It is shown that the mechanical strain present in the vicinity of the geometrical interface between the constituents of the bilayer can induce a non-negligible contribution to the TMOKE and the Imbert–Fedorov shift (IFS) for incidence angles close to those satisfying the half-wave condition for both layers, at which neither the TMOKE nor the transverse shift would appear in the absence of strain. We analyze the dependence of the IFS on the state of polarization of the incident

Complex waveguide based on a magneto-optic layer and a dielectric photonic crystal

Abstract We theoretically investigate the dispersion and polarization properties of the electromagnetic waves in a multi-layered structure composed of a magneto-optic waveguide on dielectric substrate covered by one-dimensional dielectric photonic crystal. The numerical analysis of such a complex structure shows polarization filtration of TE- and TM-modes depending on geometrical parameters of the waveguide and photonic crystal. We consider different regimes of the modes propagation inside such a structure: when guiding modes propagate inside the magnetic film and decay in the photonic crystal; when they propagate in both magnetic film and photonic crystal.

Nonlinear magneto-optic ellipsometry

The ellipsometric parameters for light reflection from a dielectric film with Kerr optical nonlinearity on a bigyrotropic magneto-electric film are theoretically investigated. The combined contributions of cubic optical nonlinearity and magneto-electric coupling allow us to control the ellipsometric parameters and thus, for example, the Kerr rotation with the incoming light intensity, in particular at incidence angles close to the pseudo-Brewster angle.

Lateral Shift of the Light Transmitted through a 1D Superconducting Photonic Crystal

We investigate the lateral shift of the light transmitted through one-dimensional photonic crystal composed of two dielectric and one superconducting sublayeres. The variations of the transmittivity spectra and the lateral shift with the temperature have been investigated for both TE-and TM-polarized oblique incident light.