A generator of duality modulated radiation, of which the irradiance, the
wave intensity, or both, are varied from ordinarily equivalent levels,
either for purposes of providing energy depleted or energy enriched
radiation or for purpose of encoding an information signal. Various
techniques are disclosed for restoring irradiance levels to "ordinary"
levels, or for amplifying irradiance without affecting wave intensity. A
communication system employing duality modulated radiation is also
disclosed.