A waveguide conduit is constructed and adapted to capture the light emitted by the at least one nano-resonant structure. The nano-resonant structure emits light in response to excitation by a beam of charged particles, The source of charged particles may be an ion gun, a thermionic filament, a tungsten filament, a cathode, a field-emission cathode, a planar vacuum triode, an electron-impact ionizer, a laser ionizer, a chemical ionizer, a thermal ionizer, or an ion-impact ionizer.