  Topological magnon insulators are the bosonic analogs of electronic
topological insulators. They are manifested in magnetic materials with
topologically nontrivial magnon bands as realized experimentally in a
quasi-two-dimensional (quasi-2D) kagome ferromagnet Cu(1-3, bdc), and they also
possess protected magnon edge modes. These topological magnetic materials can
transport heat as well as spin currents, hence they can be useful for
spintronic applications. Moreover, as magnons are charge-neutral spin-${\bf 1}$
bosonic quasiparticles with a magnetic dipole moment, topological magnon
materials can also interact with electromagnetic fields through the
Aharonov-Casher effect. In this report, we study photoinduced topological phase
transitions in intrinsic topological magnon insulators in the kagom\'e
ferromagnets. Using magnonic Floquet-Bloch theory, we show that by varying the
light intensity, periodically driven intrinsic topological magnetic materials
can be manipulated into different topological phases with different sign of the
Berry curvatures and the thermal Hall conductivity. We further show that, under
certain conditions, periodically driven gapped topological magnon insulators
can also be tuned to synthetic gapless topological magnon semimetals with
Dirac-Weyl magnon cones. We envision that this work will pave the way for
interesting new potential practical applications in topological magnetic
materials
