Title: Unidirectional control of optically induced spin waves,
Abstract: Unidirectional control of optically induced spin waves in a rare-earth iron
garnet crystal is demonstrated. We observed the interference of two spin-wave
packets with different initial phases generated by circularly polarized light
pulses. This interference results in unidirectional propagation if the
spin-wave sources are spaced apart at 1/4 of the wavelength of the spin waves
and the initial phase difference is set to pi/2. The propagating direction of
the spin wave is switched by the polarization helicity of the light pulses.
Moreover, in a numerical simulation, applying more than two spin-wave sources
with a suitable polarization and spot shape, arbitrary manipulation of the spin
wave by the phased array method was replicated.