  The Dzyaloshinskii-Moriya (DM) interaction plays an essential role in novel
topological spintronics, and the ability to control this chiral interaction is
of key importance. Developing a general microscopic framework to compute
nonequilibrium DM interactions, we theoretically show that the ac electric
field component of a laser pulse induces nonequilibrium static DM interactions
in an antiferromagnetic (AFM) system in the presence of relativistic spin-orbit
coupling. These nonequilibrium DM interactions might even be anisotropic
depending on the direction of magnetic moments and the laser pulse
polarization. We further show that intense polarized laser pulses can in
principle generate both classes of DM interactions, i.e., bulk-type and
interfacial-type, in a magnetic system even though the crystal symmetry
prohibits one of them in equilibrium. Our results reveal another aspect of rich
behavior of periodically driven spin systems and the far-from-equilibrium
magnetic systems.
