In a first exemplary embodiment of the invention, an externally and photonically energized unit comprises a shaped resonant cavity, with selected material for converting the incident photons into other electromagnetic radiation for resonance within the cavity; and a pick-up element for receiving and applying the resonant electromagnetic radiation to one or more components external to the resonant cavity. In a wideband modulation mode, the resonant cavity contains a modulation element to which a first information signal is applied. When photons, such as from an x-ray burst, traverse the resonant cavity, a wideband RF signal is generated within the resonant cavity which is modulated by the information signal. In further embodiments, the resonant cavities provide local power based on the remotely sourced photonic wave, as well as enhanced detectors.