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.
@article{arxiv.1705.03349,
title = {Unidirectional control of optically induced spin waves},
author = {Isao Yoshimine and Yoshito Y. Tanaka and Tsutomu Shimura and Takuya Satoh},
journal= {arXiv preprint arXiv:1705.03349},
year = {2017}
}