Non-specular reflection of a narrow spatially phase-modulated Gaussian beam.

The lateral and angular Goos-Hänchen shifts undergone upon reflection on a dielectric plate by a spatially phase-modulated Gaussian beam are derived. It is shown that the amplitude and direction of both lateral and angular shifts are very sensitive to the degree of spatial phase modulation of the incident beam, so that such modulation thus provides a means to control those shifts. It is also shown that the modulation incurs some beam reshaping upon reflection. Analytical calculations of the lateral shift are found to be in good agreement with numerical simulations of beam propagation before and after reflection. In these simulations, the required spatial transverse phase modulation is achieved by focusing a microwave Gaussian beam onto the dielectric plate with a non-spherical lens or a flat-surfaced thin lamella exhibiting a suitable gradient of its refractive index. The optimal parameters governing the spatial phase modulation are discussed to achieve: (i) enhancement of the lateral shift of a spatially phase-modulated beam in comparison to that of a non-modulated beam and (ii) simultaneous large values of reflectivity and of the lateral shift, while keeping the reshaping of the reflected beam to a minimum.

Three-periodic 1D photonic crystals for designing the photonic optical devices operating in the infrared regime.

We investigate theoretically and numerically one-dimensional three-periodic photonic crystals of the structure [(SiO2/TiO2)N(Al2O3/ZrO2)M]K, formed by dielectric oxides SiO2, TiO2, Al2O3, and ZrO2 (N and M are the number of subperiods, and K is the number of superperiods). We study the transmission spectra, energy and power fluxes of TE- and TM-polarized electromagnetic waves for a photonic crystal, characterized by the sharp PBG edges, and narrow and pronounced peaks of defect modes. The angular distance (difference in the incidence angles) between the transmission peaks of different polarizations is shown to be about 1.5°, which is 5 times more than in the ternary photonic crystals. The results can be useful for designing highly efficient optical devices operating in the infrared regime on the side-surface of the photonic crystal, such as polarization-sensitive couplers and angle sensors for optical fiber systems.

Goos-Hänchen effect for Brillouin light scattering by acoustic phonons.

The lateral shift of an optical beam undergoing Brillouin light scattering on an acoustic wave (AW) in the total internal reflection geometry is studied theoretically. It is shown that the lateral shift depends on polarization (longitudinal or transversal) of the AW, as well as on the type of scattering process: a direct one, when the scattered wave undergoes a lateral shift at reflection from the interface, or a cascading one, when a fundamental frequency light beam is laterally shifted at reflection and then scattered on the AW.

Hartman effect for spin waves in exchange regime.

Hartman effect for spin waves tunnelling through a barrier in a thin magnetic film is considered theoretically. The barrier is assumed to be created by a locally increased magnetic anisotropy field. The considerations are focused on a nanoscale system operating in the exchange-dominated regime. We derive the formula for group delay τgr of a spin wave packet and show that τgr saturates with increasing barrier width, which is a signature of the Hartman effect predicted earlier for photonic and electronic systems. In our calculations, we consider the general boundary conditions which take into account different strength of exchange coupling between the barrier and its surrounding. As a system suitable for experimental observation of the Hartman effect we propose a CoFeB layer with perpendicular magnetic anisotropy induced by a MgO overlayer.