  We analyze theoretically magnetoresistance of high mobility two-dimensional
electron systems being illuminated by multiple radiation sources. In
particular, we study the influence on the striking effect of microwave-induced
resistance oscillations. We consider moderate radiation intensities without
reaching the zero resistance states regime. We use the model of
radiation-driven Larmor orbits extended to several light sources. First, we
study the case of two different radiations polarized in the same direction with
different or equal frequencies. For both cases we find a regime of
superposition or interference of harmonic motions. When the frequencies are
different, we obtain a modulated magnetoresistance response with pulses and
beats. On the other hand, when the frequencies are the same, we find that the
final result will depend on the phase difference between both radiation fields
going from an enhanced response to a total collapse of oscillations, reaching
an outcome similar to darkness. Finally, we consider a multiple photoexcitation
case (three different frquencies) where we propose the two-dimensional electron
system as a potential nanoantenna device for microwaves.
