  We investigate the photon pumping effect in a topological model consisting of
a periodically driven spin-1/2 coupled to a quantum cavity mode out of the
adiabatic limit. In the strong-drive adiabatic limit, a quantized frequency
conversion of photons is expected as the temporal analog of the Hall current.
We numerically establish a novel photon pumping phenomenon in the
experimentally accessible nonadiabatic driving regime for a broad region of the
parameter space. The photon frequency conversion efficiency exhibits strong
fluctuations and high efficiency that can reach up 80% of the quantized value
for commensurate frequency combinations. We link the pumping properties to the
delocalization of the corresponding Floquet states which display multifractal
behavior as the result of hybridization between localized and delocalized
sectors. Finally we demonstrate that the quantum coherence properties of the
initial state are preserved during the frequency conversion process in both the
strong and ultra-weak-drive limit.
