Victor Dmitriev

Compact three-port optical two-dimensional photonic crystal-based circulator of W-format

A three-port optical circulator of W-format based on 2D photonic crystal is presented. This circulator is more compact as compared to the known one of the traditional Y-format. The W-circulator does not have rotational symmetry. As a consequence, the frequency responses for different port excitation are slightly different, as it is shown by symmetry analysis and by numerical simulations.

Compact optical switch based on 2D photonic crystal and magneto-optical cavity

A compact optical switch based on a 2D photonic crystal (PhC) and a magneto-optical cavity is suggested and analyzed. The cavity is coupled to two parallel and misaligned PC waveguides and operates with dipole mode. When the cavity is nonmagnetized, the dipole mode excited by a signal in the input waveguide has a node in the output waveguide. Therefore, the input signal is reflected from the cavity. This corresponds to the state off of the switch. Normal to the plane of the PhC magnetization by a dc magnetic field produces a rotation of the dipole pattern in the cavity providing equal amplitudes of the electromagnetic fields in the input and the output waveguides. This corresponds to the state on with high transmission of the input signal. Numerical calculations show that at the 1.55 μm wavelength the device has the insertion loss -0.42 dB in the on state, the isolation -19 dB in the off state and the switch off and on ratio P(on)/P(off) about 72. The frequency band at the level of -15 dB of the resonance curve in off state is about 160 GHz.

Nonreciprocal optical divider based on two-dimensional photonic crystal and magneto-optical cavity

We suggest and analyze a new nonreciprocal optical device based on two-dimensional photonic crystal and a magneto-optical cavity that simultaneously fulfills two functions: division of the input signal and isolation of the input port from two output ones. At the central frequency, the division of the signal between the output ports is -3 dB and the isolation of the input port from the output ones is about -25 dB. For the level -20 dB of this isolation, the calculated bandwidth is around 100 GHz at the wavelength 1.5 μm.

Theoretical investigation of compact microstrip resonators with stubs for patch antennas

The influence of the stubs on the resonance frequency and on the susceptance slope parameter of the disc resonator is investigated theoretically. It is shown that the stubs may significantly reduce the diameter of the resonator at the expense of bandwidth.

FDTD Formulation for Graphene Modeling Based on Piecewise Linear Recursive Convolution and Thin Material Sheets Techniques

A finite-difference time-domain formulation based on piecewise linear recursive convolution method and on thin material sheets technique is developed for modeling terahertz graphene antennas and some other photonic components. The graphene sheets are modeled by specific recursive equations obtained for tangential electric field components, allowing one to easily apply voltage or current sources between the sheets. The effective conductivity of graphene sheets in Yees three-dimensional lattice is calculated and used in simulations. A bow-tie-like geometry is investigated, aiming at resonance tuning. The developed numerical formulation is validated by comparison of results to data published in literature.

Enhancement of Faraday and Kerr rotations in three-layer heterostructure with extraordinary optical transmission effect

We theoretically investigate and optimize a multilayer planar structure with enhanced magneto-optical (MO) activity. The extraordinary optical transmission observed in a periodically perforated metal plate with subwavelength holes is used to produce a higher MO activity. We consider a three-layer structure that consists of a dielectric layer placed between the perforated metal and the MO layers. In this structure, we obtained the enhancement of Faraday rotation by three times and the Kerr effect by an order as compared to the published results.

Planar Monopole UWB Antennas with Cuts at the Edges and Parasitic Loops

In this paper, we analyze an antenna for application in ultra wideband systems. This antenna is composed by one planar monopole with cuts at the edges and two parasitic loops. The numerical analysis of the antenna was done by the Method of Moments (MoM). For comparison, some of the calculations were also made by the commercial software IE3D. The results of this analysis show that the antenna has excellent impedance matching in all frequency range of UWB systems.

Graphene nanoantennas with different shapes

In this paper we present a numerical analysis of graphene nanoantennas with rectangular, elliptical, triangular and circular geometries in terahertz band. We model the electromagnetic scattering of these planar structures by the method of moments with the surface impedance of graphene. We analyze the absorbing cross section and the resonances of nanoantennas for different, sizes, chemical potential, temperature and incident angle. The obtained results can be useful to design efficient nanoantennas for terahertz wireless communications.

Possible mechanisms of switching in symmetrical two-ports based on 2D photonic crystals with magneto-optical resonators

We analyze possible mechanisms of switching in two-ports based on 2D photonic crystals (PhCs) with a magneto-optical resonator. The input and output waveguides can be side or front coupled with the resonator. The resonator operates with a dipole mode. In the switch with front coupling in the nonmagnetic state the standing dipole mode provides equal nonzero wave amplitudes in the input and output waveguides and therefore transmission of the signal from the input to output waveguides. This is the state on. The applied magnetic field normal to the plane of the PhC rotates the standing dipole mode by 90° setting the nodes in the input and output waveguides. This corresponds to the state off. On the contrary, in the switch with side coupling and nonmagnetized resonator, the standing dipole mode excited by a wave in the input waveguide has its node in the output waveguide. Therefore, the signal is reflected from the input port. This corresponds to the state off of the switch. Magnetization by a DC magnetic field produces a rotating dipole pattern in the cavity. Due to this rotating, the mode signal passes from the input port to the output one and this is the state on.

BOWTIE NANOANTENNAS WITH POLYNOMIAL SIDES IN THE EXCITATION AND EMISSION REGIMES

In this work, we analyze modifled bowtie nanoantennas with polynomial sides in the excitation and emission regimes. In the excitation regime, the antennas are illuminated by an incident plane wave, and in the emission regime, the excitation is fulfllled by inflnitesimal electric dipole positioned in the gap of the nanoantennas. Several antennas with difierent sizes and polynomial order were numerically analyzed by method of moments. The results show that these novel antennas possess a controllable resonance by the polynomial order and good characteristics of near fleld enhancement and conflnement for applications in enhancement of spontaneous emission of a single molecule.