Emission of surface electromagnetic waves in the case of resonance tunneling of electrons

A calculation is made of the spectral density of the intensity of surface electromagnetic waves excited by the passage of a current across metal–barrier–metal tunnel structures when there are quantum potential wells inside the barrier. It is shown that quasilevels in these quantum wells give rise to narrow peaks in the spectrum of the excited surface electromagnetic waves and that the quantum efficiency of the excitation of such waves by tunneling electrons can reach unity. The peak positions can be controlled by altering the voltage across a tunnel structure.