  We demonstrate the emergence of a non-equilibrium superradiant phase in the
dissipative Rabi-Dicke model. This phase is characterized by a photonic steady
state that oscillates with a frequency close to the cavity frequency, in
contrast to the constant photonic steady state of the equilibrium superradiant
phase in the Dicke model. We relate this superradiant phase to the population
inversion of Floquet states by introducing a Schwinger representation of the
driven two-level systems in the cavity. This inversion is depleted near Floquet
energies that are resonant with the cavity frequency to sustain a coherent
light-field. In particular, our model applies to solids within a two-band
approximation, in which the electrons act as Schwinger fermions. We propose to
use this Floquet-assisted superradiant phase to obtain controllable optical
gain for a laser-like operation.
