Optical excitation of spin waves in all-dielectric nanostructured materials with iron garnet

Launching and controlling magnons by optical excitation opens up new opportunities for applications in magnonics and information processing. Laser excitation of spin waves provides control over propagation pattern, type of the launched waves, phase and amplitude, and lateral positioning of the source. The origin of the nonthermal excitation of spin waves by circular polarized pulses is in the inverse Faraday effect (IFE). In this work we demonstrate a novel approach to enhance and manipulate the IFE via excitation of TM-polarized guided modes in all-dielectric layered and PC-based waveguide structures based on bismuth-substituted iron garnet films. The special feature of these structures is that they allow the excitation of the IFE by linear polarization of a laser pulse. Moreover, the non-uniform distribution of the effective magnetic field induced by the laser results in the excitation of the exchange spin modes. We demonstrate the method of spin waves excitation that provides the possibility to effectively excite different eigenmodes in the system by tuning the parameters of the pump that determine the initial configuration of IFE field.