Excitation of spin waves of a required frequency and directional spectrum is among the crucial tasks in optomagnonics. Here we investigate the generation of spin waves in an iron garnet thin film by a train of femtosecond laser pulses with ultimately high repetition rate of up to 10 GHz and compare it with the case of 1-GHz repetition rate. The periodic optical excitation with repetition rate close to the frequency of the ferromagnetic resonance amplifies spin waves with particular phase velocity and wavelength, which are tunable across a wide range by small variations of the frequency detuning, and can be adjusted by the magnitude of the applied external magnetic field. For pulses of the same fluence, the 10-GHz pulse rate provides a significant resonant increase of the spin-wave amplitude by 11.5 times with respect to single-pulse excitation while the 1-GHz pulse rate provides only a 1.5 times advancement. Moreover, variation of the detuning frequency provides different regimes of the spin-wave propagation: short-and long-distance propagation along the magnetic field direction and appearance of an "X" line shape in the directionality pattern, making the considered optical approach of spin-wave generation promising for designing magnonic devices.

Spin waves in magnetic microresonators are at the core of modern magnonics. Here we demonstrate a new method of tunable excitation of different spin wave modes in magnetic microdisks by using a train of laser pulses coming at a repetition rate higher than the decay rate of spin precession. The microdisks are etched in a transparent bismuth iron garnet film and the light pulses influence the spins nonthermally through the inverse Faraday effect. The high repetition rate of the laser stimulus of 10 GHz establishes an interplay between the spin wave resonances in the frequency and momentum domains. As a result, scanning of the focused laser spot near the disk boarder changes interference pattern of the magnons and leads to a resonant dependence of the spin wave amplitude on the external magnetic field. Apart from that, we achieved a switching between volume and surface spin waves by a small variation of the external magnetic field.

We present a concept of a tunable optical excitation of spin waves and filtering their spectra in a ferromagnetic film with 180 degrees Neel domain wall. We show by means of micromagnetic simulation that the fluence of the femtosecond laser pulse and its position with respect to the domain wall affect the frequencies of the excited spin waves, and the presence of the domain wall plays crucial role in control of the spin waves' spectrum. The predicted effects are understood by analyzing the changes of the spin waves' dispersion under the impact of the laser pulse.

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical response that allows for the simultaneous measurements of the surface and bulk refractive index of the analyzed substance. The approach is based on two different spectral features of the magneto-optical response corresponding to the resonances in p- and s-polarizations of the incident light. Angular spectra of p-polarized light have a step-like behavior near the total internal reflection angle which position is sensitive to the bulk refractive index. S-polarized light excites the TE-polarized optical Tamm surface mode localized in a submicron region near the photonic crystal surface and is sensitive to the refractive index of the near-surface analyte. We propose to measure a hybrid magneto-optical intensity modulation of p-polarized light obtained by switching the magnetic field between the transverse and polar configurations. The transversal component of the external magnetic field is responsible for the magneto-optical resonance near total internal reflection conditions, and the polar component reveals the resonance of the Tamm surface mode. Therefore, both surface- and bulk-associated features are present in the magneto-optical spectra of the p-polarized light.

Here we demonstrate a novel magnetoplasmonic heterostructure for efficient control of light. It consists of gold nanoparticles embedded in a thin magnetic film covered with a gold layer pierced with periodic nanoslit array. Unique feature of the proposed structure is that it supports four different types of optical modes in the same frequency range including localized and propagating surface plasmons along with waveguide modes. A peculiar magneto-optical response appears at the frequencies of the mode hybridization. The most important result comes from hybridization of the localized and propagating plasmons leading to a significant increase of the magneto-optical effect intensity.

The inverse Faraday effect induced in magnetic films by ultrashort laser pulses allows excitation and control of spins at gigahertz and sub-terahertz frequencies. The frequency of the optically excited magnetization precession is easily tunable by the external magnetic field. On the other hand, the initial phase of the precession marginally depends on the magnetic field. Here we demonstrate an approach for the control of the precession phase by variation of the pump beam direction. In particular, we consider the case when the magnetization precession is excited by obliquely incident pump pulses in a magnetic dielectric film placed in the in-plane magnetic field.Theoretical consideration predicts that the initial phase should appear for a non-zero in-plane component of the pump wavevector orthogonal to the external magnetic field. Experimental studies confirm this conclusion and reveal that the phase grows with increase of the in-plane wavevector component. Variation of phase by 15 deg is demonstrated. Potentially, the phase could be changed even more pronouncedly by more than 90 deg. This work provides a simple way for additional manipulation with optically excited magnetization dynamics, which is of importance for different spintronic applications.

Nowadays, spintronics considers magnetic domain walls as a kind of nanodeviсe that demands for switching much less energy in comparison to homogeneous process. We propose and demonstrate a new concept for the light control via electric field applied locally to a magnetic domain wall playing the role of nanodevice. In detail, we charged a 15-μm-thick metallic tip to generate strong non-uniform electric field in the vicinity of the domain wall in the iron garnet film. The electric field influences the domain wall due to flexomagnetoelectric effect and causes the domain wall shift. The resulting displacement of the domain wall is up to 1/3 of domain width and allows to demonstrate a novel type of the electrically controlled magneto-optical shutter. Polarized laser beam focused on the electric-field-driven domain wall was used to demonstrate the concept of a microscale Faraday modulator. We obtained different regimes of the light modulation – linear, nonlinear and tri-stable – for the same domain wall with corresponding controllable displacement features. Such variability to control of domain wall’s displacement with spatial scale of about 10 μm makes the proposed concept very promising for nanophotonics and spintronics.

We consider a scheme of Faraday magneto-optical light modulator with local magnetization control via magneto-electric effect. Our earlier researches of bismuth-substituted iron garnets films showed the giant domain wall (DW) displacement in electric field of charged tip due to magneto-electric effect [1, 2]. The displacement gives the opportunity to the local magnetization switching on the spatial scales about few microns.