  The developments in the field of quantum optics raise expectations that
laser-matter coupling is a promising building block for magnonics. Here, we
propose a method for the generation of direct and alternating spin currents of
magnons across the junction interface irradiated by linearly polarized laser.
In a junction of ferromagnetic insulators with a large electronic gap, the spin
angular momentum is exchanged during the tunneling process of magnons across
the junction interface. The advanced technology in the field of plasmonics and
metamaterials realizes that spins irradiated by the laser field interact only
with the magnetic component of the laser through the Zeeman coupling. Using an
analytic perturbation theory, we provide a general formula for magnon transport
induced by the inversion symmetry breaking across the junction interface. Then,
we show that those spin currents are enhanced by the ferromagnetic resonance,
and the period of the ac spin current is one-half of that of the laser magnetic
field. Finally, we estimate the magnitude of the spin current, and find that it
will be within experimental reach.
