Dmitry G. Sannikov

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.

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.

Influence of annealing on the diffusion characteristics and optical losses of multimode Ag+-glass waveguides ☆

Abstract In the recent paper the experimental investigation of changes of optical and diffusion characteristics of multimode Ag+-glass waveguides in the process of annealing is presented. It has been shown that the process of refractive index profile redistribution in investigated samples had irregular and step-by-step character. At first the refractive index in the underlying waveguide layers increased because of a silver ions outflow from near-surface regions. Then silver ions started to migrate all over the waveguide profile and finally the silver ion concentration did not vary significantly in the medium layers of waveguide but the waveguide length kept growing. The refractive index profile redistribution was accompanied by change of waveguide mode losses. Experimental results let us conclude that major sources of optical losses were the microscopic metallic conglomerates in the waveguide region. During annealing their concentration in the near surface region decreased at first and then increased while in the underlying regions their concentration practically did not change. The space and temporal dependences of diffusion coefficients of the ion-exchanged process of silver ions in glass have been obtained in the result of the inverse diffusion problem solution. The maximum value of the diffusion coefficient was about 2.73×10 −15 m 2 / s .

Difference-Frequency Generation of THz Radiation via Parametric Three-Wave Interaction in CdTe and ZnTe Crystals

Difference-frequency generation of terahertz (THz) radiation in a collinear single-crystal scheme with distributed feedback implemented by means of parametric interaction of counterpropagating optical waves in a periodically inhomogeneous medium exhibiting quadratic nonlinearity is investigated. Using ZnTe and CdTe crystals optically pumped at λ = 0.77 and 1.06 μm, respectively, as an example, the possibility of obtaining parametric generation of THz radiation with an optical-to-THz conversion efficiency exceeding 10–3 (with an extremely narrow line of oscillation of less than 4 GHz for ZnTe and less than 9 GHz for CdTe at 1 THz) is demonstrated in the undepleted-pump-intensity approximation. The obtained results can be used for construction of narrow-band lasers in the THz frequency range with an output power (in the quasicw regime of oscillation) of about 105 W/cm2.

One-dimensional dielectric bi-periodic photonic structures based on ternary photonic crystals

We investigate the transmittivity spectra, fields, and energy distribution of the electromagnetic eigenwaves propagating in a one-dimensional (1D) dielectric photonic crystal [(TiO2/SiO2)NAl2O3]M with two periods formed by unit cells TiO2/SiO2 and (TiO2/SiO2)NAl2O3. Spectra of TE- and TM-modes depend on the geometric parameters of the structure and undergo modifications with the change in the period numbers, layer thicknesses, and incidence angle. Special attention is paid to the applicability of the hybrid effective medium approximation comprising the long-wave approximation and two-dimensional (2 × 2) transfer matrix method. We demonstrate spectral peculiarities of the bi-periodic structure and also show the differences between the band gap spectra of the bi-periodic and ternary 1D dielectric photonic crystals. The presented photonic crystal structure can find its applications in optoelectronics and nanophotonics areas as omnidirectional reflectors, optical ultra-narrow bandpass filters, and antireflect...

Transmission spectra of one-dimensional bi-periodic photonic crystals

We investigate the transmittivity spectra of the electromagnetic waves for 1D bi-periodic dielectric photonic crystals of the structure [(AB)^NC]^M(AB)^N created on basis of the oxide layers TiO<inf>2</inf>, SiO<inf>2</inf> and Al<inf>2</inf>O<inf>3</inf>. The spectra modifications with the change of the incidence angle of light, period numbers and the layers thicknesses are considered.

Magneto-optic waveguide and dielectric photonic crystal as a new complex structure for photonics

The dispersion and polarization properties of the electromagnetic waves in a multilayered structure composed of a magneto-optic waveguide on dielectric substrate covered by a one-dimensional dielectric photonic crystal are investigated theoretically. Different regimes of modes propagation inside such structure depending on the system parameters are studied.

Complex photonic structure based on magneto-optic waveguide and photonic crystal

We investigate theoretically the dispersion and polarization properties of the electromagnetic waves in a magneto-optic waveguide on the substrate covered by one-dimensional photonic crystal. The numerical analysis of such a complex structure shows peculiarities in dispersion spectra of TE- and TM-modes, depending on geometrical parameters of the waveguide and photonic crystal.

Optical properties of a four-layer waveguiding nanocomposite structure in near-IR regime

We present a theoretical study of the optical properties of TE- and TM- modes in a four-layer structure composed of a magneto-optical yttrium iron garnet guiding layer on a dielectric non-magnetic substrate covered by a planar nanocomposite guiding multilayer. We examine important issues for TM-modes, calculate and compare in details the dispersion spectra and the energy flux distributions across the structure for TE- and TM-modes of different orders and show new features concerning the splitting, switching and filtration possibilities of the fundamental modes of the orthogonal polarizations. The presented theoretical approach may be utilized for designing of different magneto-optical devices with preselected optical properties.

Hybrid magnetic waveguide and dielectric photonic crystal structure

We theoretically investigate the dispersion and polarization properties of the electromagnetic waves in a multi-layered structure composed of a magneto-optical waveguide on dielectric substrate covered by 1D dielectric photonic crystal. The numerical analysis of such a complex structure shows interesting properties in propagation of electromagnetic waves, particularly, polarization filtration of TE- and TM-modes depending on geometrical parameters of waveguide and photonic crystal.