A. P. Sukhorukov

Transformation of mode polarization in gyrotropic plasmonic waveguides

We analyze the gyration impact on the mode polarization in plasmonic waveguides containing dielectrics with natural optical activity, or gyration induced by magnetization in the polar configuration or the longitudinal configuration. It has been found that the gyration mostly affects the mode polarization that acquires additional optical field components proportional to the gyration coefficient, whereas the mode dispersion remains almost unchanged. Moreover, if the gyration coefficient is rather large, then the mode loses its localization. The polarization transformation can be two orders of magnitude stronger for structures with a thin metal film than that for the solitary interface. The polarization transformation of the plasmonic modes was demonstrated experimentally via measuring optical transmittance through a layered magnetoplasmonic structure. The resonance in the transmittance spectrum corresponding to the excitation of modes of the polarization orthogonal to that of incident light was observed. The polarization transformation is enhanced if the TM and TE modes are excited simultaneously. The described effect can be applied in sensors, plasmonic circuitry, and plasmonic-based light modulators.

Total reflection, frequency, and velocity tuning in optical pulse collision in nonlinear dispersive media

The total internal reflection of a weak signal pulse from a powerful reference pulse at another frequency in a dispersive nonlinear medium is demonstrated. As a result of the two-wave collision, the signal pulse changes its frequency and group velocity, and time delay occurs. We develop both a wave and a pulse-tracing theory of the total reflection from the moving inhomogeneity induced by the optical pulse. An analytical expression for the critical value of group-velocity mismatch as a function of pump intensity and the group-velocity dispersion are obtained. The possibility of signal pulse reflection from a bright soliton in a cubic medium is considered.

Finite Integration Technique capabilities for indoor propagation prediction

3D Finite Integration Technique (FIT) has been applied to radio propagation calculations over areas up to 400 m2 with computing time of less than 3 hours on a single-processor computer and frequency range of up to 1 GHz. Numerical effort of FIT Maxwells equations solver in time domain increases at a slower rate with the problem size than other commonly employed methods, thus larger and more complex structures may be analyzed. Measurements have shown a high accuracy of the method for field level prediction: error was in the range 2–3.7 dB with spatial detailing of prediction at wavelength scales, for a complex indoor environment, various transmitter locations and frequencies. The method also demonstrated quite accurate prediction of wideband channel characteristics (power delay profile envelope).

Structure of absorption and luminescence bands in aluminosilicate optical fibers doped with bismuth

Absorption and luminescence spectra of bismuth-doped optical fibers have been measured in the temperature range 77–1000 K. The measured spectra were approximated by Gaussian functions, and the parameters of the absorption and luminescence transitions were determined. A model of three modifications of the same bismuth center in three different environments in an aluminosilicate glass matrix is proposed.

Turbulence-induced laser-beam distortions in phase space

A consecutive analysis of spatial-temporal disturbances of a laser beam propagating through a turbulent media was carried out. Evolutionary equations for the intensity distributions were obtained for a channel with different types of regular and stochastic spatial dispersion. The relative simplicity and physical validity of the integral relationships allows one to build them in the control algorithm for jam-protection of open-space operating channels.

Nonlinear interaction and reflection of incoherent light beams

The interaction dynamics between two incoherent light beams in a medium with thermal nonlin-earity is studied both experimentally and theoretically. It is shown that in the mode of a nonlinear reflection the transformation of a spatial structure of a weak signal beam can be theoretically described in the framework of a spatially distributed model for a nonlinear change in the refractive index of the medium.

Comparative Analysis of Ray tracing, finite integration technique and empirical models using ultra-detailed indoor environment model and measurements

3D Finite Integration Technique (FIT), ray tracing and simple empirical model accuracy is compared on a single basis, using a high-detailed environment model. The most accurate FIT Maxwells equations solver demonstrated very high precision (1.1 – 2.4 dB) when compared with measurements in a complex indoor environment, thus validating the environment model and measurement campaign for ray tracing accuracy estimation. The comparison of methods has been made generally in terms of accuracy of narrowband (field level spatial distributions) and wideband (power delay profiles) channel characteristics prediction as well as required computing resources. Another contribution of current work is the investigation of the prediction accuracy dependence on the spatial detailing of prediction (size of spatial averaging window as an example). It is shown that prediction accuracy increases significantly with the decrease in spatial detailing of prediction, though in some cases the increase in accuracy is not monotonic. The impact of the environment model detail and its spatial size on the accuracy of predictions is also investigated. The environment model included double-framed windows, doors, metallic objects, some meaningful furniture, along with precision geometry.

Tunneling of Optical Beams through Inhomogeneity of a Refractive Index

We consider the effect of tunneling of optical beams through a narrow induced inhomogeneity in a refractive index. It is shown that under the condition of total internal reflection from the induced channel, part of the signal beam leaks if the channel is narrow. Dependence of the pump beam width at which the tunneling of half signal power occurs is found as a function of the pump intensity and the angle of beam crossing.

Nonlinear effects upon collisions of optical pulses: Tunneling, blocking, and trapping

The regimes of reflection, trapping, and tunneling of light pulses upon their collision in nonlinear media are considered. General conditions for the occurrence of these phenomena in optical fibers and nonlinear crystals are formulated on the basis of an analogy with quantum mechanics.

Unique mode properties of optical metacavities

Unusual optical properties of a cavity that contains a layered structure with an alternating refractive index are considered. The layers with the negative refraction and the negative phase velocity provide for drastic changes to the properties of the longitudinal and transverse modes. The transverse-mode structure depends on the effective diffraction length whereas the spectrum of longitudinal modes is determined by the effective optical length of the cavity. The effective lengths can be positive, negative, or zero. In the last case, the transverse distribution of the amplitude can be arbitrary. The conditions for the stability of the metacavity are derived. It is demonstrated that an unstable empty cavity becomes stable when a metamaterial is introduced inside it.