Ultrafast spin manipulation - Opto-magnonics
We investigate ultrafast coherent spin manipulation of magnetic materials by using femtosecond laser pulses and terahertz pulses. (Sub)terahertz spin precessions have been nonthermally induced by circularly polarized pulses. We also study imaging of spin wave propagation in ferrimagnets excited by optical pulses. We propose a principle to synthesize spin wave by using a spatially shaped light pulse with circular polarization. We controlled the direction of the energy flow by shaping the light spot into an ellipse with its major axis parallel or perpendicular to the magnetic field.
