Transmission spectra of a microresonator structure with Bragg mirrors are obtained. A quarter-wave plate made of extrinsic semiconductor is installed in the working cavity. The properties of such a semiconductor can be controlled using external magnetic field. It is shown that variations in the external field, cavity size, and position of the active layer lead to modification of the photonic spectrum of the TM and TE eigenwaves. Splitting of a defect mode at the center of the band gap into two modes takes place when the active layer is placed in the cavity. The evolution of such modes caused by variations in the magnetic field is studied. Dependences of the size and number of stopbands on the structural parameters, frequency, and field are determined, and maps of band gaps are obtained.

It is shown that when counterpropagating laser beams are incident on an array of parallel single-walled carbon nanotubes, strong interaction of waves is possible, accompanied by the amplification of one of the waves at the expense of another, more intense pump wave. The interaction is most efficient when the condition of phase matching of the incident waves and the slow plasmon polariton wave formed because of the laser-induced metallisation of nanotubes is satisfied. The dependence of the the signal wave gain on the geometric parameters of the array and the wave characteristics of the incident waves is studied numerically. A range of phase detuning values is found, in which the gain changes weakly near its maximum value.

A numerical analysis of the phase-matching conditions during the incidence of one or two counterpropagating laser beams on an ordered array of single-walled carbon nanotubes (CNTs) is performed. The conditions for the generation of slow surface plasmon waves of the terahertz (THz) and far infrared range propagating along the nanotubes of the irradiated array are determined. It is shown that the plasmon frequency can be controlled by changing the angle of incidence of laser radiation on the structure under study. Thus, it is possible to fulfill the condition of longitudinal resonance, in which each array nanotube is a dipole antenna radiating at the plasmon frequency. In this case, the array forms a system of a large number of in-phase emitters, which allows increasing the efficiency of conversion of laser radiation into THz radiation in comparison with a single nanoantenna.

AbstractTunneling of microwave radiation through a symmetric three-layer structure in which the central ferrite layer is interfaced with two layers of a material with negative permittivity is considered. Conditions for perfect tunneling (i.e., transmission with zero reflection) are analyzed for normal incidence. It is shown that the transmittance of the structure can be controlled using external magnetic field that provides magnetization of the ferrite layer. A broad transmission band with a width of several gigahertzes in which almost perfect tunneling is implemented can exist in the frequency range corresponding to the negative effective permeability of the ferrite material.

The incidence of two coherent waves traveling in opposite directions on opposite surfaces of a planar layered-periodic graphene–dielectric structure has been investigated. It has been shown in the long-wave approximation that it is possible to control the intensity of the outgoing waves and absorption of radiation in the structure by changing the phase difference of the waves that are incident on the structure. There are close to optimal conditions for the intensity modulation effect in the terahertz frequency domain and modulation of the absorption capacity of the structure is possible in the near infrared and visible ranges.

The incidence of two counterpropagating coherent waves on the opposite surfaces of a planar periodically layered graphene – dielectric structure was studied. In the long-wave approximation, it is shown that, due to the variation of the phase difference of waves incident on the structure, it is possible to control the intensity of outgoing waves and the absorption of radiation in the structure. In the terahertz frequency domain there are close to optimal conditions for the realization of the intensity modulation effect, and in the near-IR and visible ranges the modulation of the absorbance of the structure is possible.

Tunneling of microwave radiation through a symmetric three-layer structure in which the central ferrite layer is interfaced with two layers of a material with negative permittivity is considered. Conditions for perfect tunneling (i.e., transmission with zero reflection) are analyzed for normal incidence. It is shown that the transmittance of the structure can be controlled using external magnetic field that provides magnetization of the ferrite layer. A broad transmission band with a width of several gigahertzes in which almost perfect tunneling is implemented can exist in the frequency range corresponding to the negative effective permeability of the ferrite material.

The mechanism of generation of surface plasmon polaritons in the THz and far-IR ranges by laser irradiation of arrays of single-walled carbon nanotubes is considered. It is shown that by varying the angle of incidence of the laser beam, one can change the frequency of generated surface plasmon polaritons. As consequence, the nanotube length can be matched to the laser wavelength for efficient conversion of cw laser radiation to the THz range.

We have considered the tunneling of a normally incident electromagnetic wave through a bilayer structure that consists of a ferrite layer and an adjoining layer with a negative permittivity. The ferrite layer is transversely magnetized by an external magnetic field that corresponds to the range of negative values of the effective permeability. It has been shown that the transmission of the structure can be controlled in wide limits by varying the external magnetic field. In particular, nearly perfect tunneling (viz., nonreflective transmission of incident radiation) can be realized.

The oblique incidence of TE-polarized plane electromagnetic wave on a three-layered lossless structure containing the layer of double-negative medium is discussed. The resonant values of the angle of incidence are obtained, for which the perfect tunneling of electromagnetic power through the structure can be achieved. The results of exact numerical analysis are compared with approximate solution based on the model of symmetrical slab waveguide.

We have investigated the transmission ability of a layered structure the central layer of which is made of a “left-handed” material (its refractive index is negative) and is separated by two air slabs from a “right-handed” dielectric medium that surrounds the structure. We consider tunneling of energy fluxes through the structure and determine conditions for the complete (reflectionless) transmission of the power of the incident wave through it. We show that this effect is resonant and is observed when the tangential component of the wave vector of the incident wave coincides with the longitudinal wave vector of one of waveguiding eigenmodes of the left-handed layer.

Features of energy flux formation inside and outside an absorbing layer are theoretically described for the case where two coherent counter-propagating waves of identical linear polarization are obliquely incident on the opposite sides of the layer with the adjacent media exhibiting symmetric optical parameters. Dependence of the interference fluxes on the angle of incidence and thickness of the layer is established for different phase shifts of the incident waves. Conditions under which the energy density inside the layer attains the maximum value are determined.

The interference control of absorbance and transmittance of a thin magnetic layer using variations in (i) phase difference of counterpropagating coherent waves that are incident at a certain angle on opposite sides of the layer and (ii) external magnetic field is studied. It is demonstrated that the absorbance depends on the parameters of the layer. Almost total absorption and dissipation-free transmission of energy are possible for the absorbing layer.

Tunneling of monochromatic radiation obliquely incident on a plane-layered structure is investigated. In the structure, a left-handed material layer (with a negative refractive index) is surrounded by layers with positive refractive indexes. Conditions for resonance amplification of evanescent waves that occurs simultaneously with perfect tunneling, i.e., reflection-free transmission of radiation through the plane-layered structure, are revealed.

Three definitions of a refractive index that differ in the meaning of its real part are considered for a homogeneous isotropic medium. The signs of wave characteristics (a refractive index and an impedance) are determined for sixteen possible combinations of the signs of the real and imaginary parts of the permittivity and permeability of a medium.

The control of the interference heat emission upon the oblique incidence of two counterpropagating (with respect to the transverse component of the wavevector) identically linearly polarized coherent waves on the opposite sides of an absorbing layer is considered. The dependences of the interference heat emission on the angle of incidence and the layer thickness are established for various refractive indices and absorption coefficients in weakly and strongly absorbing media. The conditions for the maximum interference heat emission are determined.

Dispersion properties of circularly polarized eigenwaves propagating in the “semiconductor-magnet” layered periodic structure along the axis of its periodicity and external magnetic field have been considered. The possibility of controlling the effective material parameters of the structure and the feasibility of negative refractive index for the wave with right (resonant) circular polarization has been shown. High magneto-optical activity of this gyrotropic structure has been ascertained, which leads to large Faraday rotation angles if the structure is in the state of “left-handed” medium.