An electromagnetic energy concentrator uses a prism and waveguide with a gap layer of uniform thickness disposed between the prism and a first surface of waveguide. Energy detectors, which may be photovoltaics or miniaturized antenna elements are disposed adjacent to and co-extensive with a second surface of the waveguide. The detectors operate in each of at least two bands; a distance between detectors operating in a given band depends on a wavelength in the given band.