Odd Magneto-Optical Linear Dichroism in a Magnetophotonic Crystal

The phenomena of magneto-optical polarization rotation and circular magnetic dichroism are well known in the Faraday configuration. We present another effect, an odd magneto-optical linear dichroism, arising in nanostructures with polarization-dependent mode Q-factors. It reveals itself as the magneto-optical modulation of light intensity for the two opposite magnetization directions in the Faraday configuration. The effect was demonstrated on a magnetophotonic crystal with a cavity mode, the polarization-dependent Q-factor of which is due to oblique incidence. For a polarization angle of 60{\deg} (or 120{\deg}) and an angle of incidence around 60{\deg}, the magneto-optical intensity modulation maximizes and reaches 6%

Explosive instability of magneto-elastic Waves

Les instabilités paramétriques non linéaires (NL) ont été observées sur les ondes magnéto-élastiques dans le cas d un couplage de trois quasi-phonons sous pompage électromagnétique. La théorie en prédit une dynamique supercritique explosive, mais limitée expérimentalement par le décalage de fréquence dû aux fortes nonlinéarités. La dynamique supercritique des instabilités paramétriques NL est étudiée dans deux matériaux antiferromagnétiques "plan facile" (AFEP): l hématite a-Fe2O3 et le borate de fer FeBO3. Ces matériaux possèdent une très grande NL acoustique effective en raison du couplage magnéto-élastique élevé. Les mécanismes de limitation de la dynamique explosive ont été analysés à l'aide de l'approximation anharmonique. La compensation du décalage fréquentiel NL par une modulation de phase singulière du pompage a été proposée et théoriquement vérifiée, puis utilisée pour l observation expérimentale de la dynamique supercritique explosive des excitations de trois quasi-phonons dans les résonateurs magnéto-élastiques. Les études sur FeBO3 ont été réalisées dans la gamme de température 77 K - 293 K où les paramètres magnéto-élastiques du cristal varient de façon significative. Un modèle fortement non linéaire des excitations de trois quasi-phonons dans les AFEPs a été développé. Les simulations numériques sont en accord avec les résultats expérimentaux. Les études théoriques de couplage de trois ondes magnéto-élastiques progressives ont été effectuées sur la base de modèles théoriques prenant en compte la non-linéarité cubique des cristaux AFEP réels. Les simulations numériques prévoient un comportement explosif et une localisation spatiale des triades généréesRecently discovered nonlinear parametric instabilities occur when nonlinear parameter of a system is modulated. These instabilities were reported on magnetoelastic waves as three quasi-phonon coupling under electromagnetic pumping. Theoretical studies predicted supercritical explosive dynamics of these instabilities. Experimentally such singular behavior is limited by strong nonlinear frequency shift.Presented work studies supercritical dynamics of nonlinear parametric instabilities in two easy plane antiferromagnets (AFEP): hematite a-Fe2O3 and iron borate FeBO3. These materials possess unprecedented effective acoustic nonlinearity due to high magneto-elastic coupling. Limiting mechanisms of explosive dynamics were analyzed with the help of anharmonic approximation. Nonlinear frequency shift compensation via singular pumping field phase modulation was suggested and theoretically approbated. This technique was successfully used for experimental observation and investigation of supercritical explosive dynamics of three quasi-phonon excitations in magnetoelastic resonators. Iron borate studies were performed in the temperature range 77 K 293 K where magnetoelastic parameters of the crystal vary essentially. Strongly nonlinear model of three quasi-phonon excitations in AFEPs was developed. Numerical simulations of the model showed good agreement with experimental results.Theoretical studies of three travelling magnetoelastic waves coupling are performed on the basis of suggested theoretical models that take into account cubic nonlinearity of real AFEP crystals. Numerical simulations of the models suggest explosive behavior and spatial localization of generated triadsVILLENEUVE D'ASCQ-ECLI (590092307) / SudocSudocFranceF

Investigation of welds by the method of the magneto-optical eddy current flaw detection

The paper deals with the magneto-optical eddy current method of flaw detection of conducting materials, in which epitaxial films of ferrite garnet are used as sensors. In particular, the possibilities of visualization of welded seams in magnetic and non-magnetic samples, as well as the defectoscopy of the seams themselves, are considered. The second part of the work is devoted to mathematical modeling of the distribution of the magnetic fields of eddy currents near similar defects

Waveguide magnetoplasmonic structure based on ferrite garnet film

The magnetoplasmonic structure, which is a planar multimode magnetooptical waveguide, 10 μm thick with plasmon resonance SiO2 / Cu coating on the surface is experimentally realized. With the total length of the magnetooptical waveguide 4.6 mm and the length of the SiO2 / Cu coating equal to 3.9 mm, the insertion loss of the structure for TM- and TE-polarized light was 22 and 4 dB, respectively, at a wavelength of 1550 nm. Linearly polarized light was launched into the magneto-optical waveguide using a SMF-28 single-mode optical fiber coupled to the polished input edge of the waveguide. The structure is of interest for use as miniature magnetically controlled modulators of light intensity

Investigation of welds by the method of the magneto-optical eddy current flaw detection

The paper deals with the magneto-optical eddy current method of flaw detection of conducting materials, in which epitaxial films of ferrite garnet are used as sensors. In particular, the possibilities of visualization of welded seams in magnetic and non-magnetic samples, as well as the defectoscopy of the seams themselves, are considered. The second part of the work is devoted to mathematical modeling of the distribution of the magnetic fields of eddy currents near similar defects