A surface plasmon generator having an electric circuit, a plasmon supporting surface and first and second quantum systems (13, 15) respectively defining first and second quantum states (17, 19) with a tunneling junction being present between the first and second quantum systems (13, 15), the first and second quantum systems (13, 15) being present in the electric circuit to generate a tunneling current between the first and second quantum systems (13, 15), wherein the surface plasmon generator comprises a first electrode associated with the first quantum system and forming part of the electric circuit and a second electrode associated with the second quantum system and forming part of the electric circuit or a first electric junction between the first quantum system and the electric circuit and a second electric junction between the second quantum system and the electric circuit, wherein the quantum states (17, 19) each have an energy close to the Fermi level of their respective associated electrode (2, 5) or respective Fermi energies are established at the first and second electric junctions, whereby the plasmon supporting surface is positioned proximate to at least one of the first quantum system, the second quantum system and the tunneling junction, wherein the electric circuit comprises a voltage source that is configured to provide a voltage between the first electrode or the first electric junction and the second electrode or the second 2. electric junction, wherein the voltage causes a corresponding energy difference between the Fermi level of the first electrode or the Fermi energy established at the first electric junction and the Fermi level of the second electrode or the Fermi energy established at the second electric junction, wherein the energy levels of the first and second quantum states (17, 18) shift in the same way as the Fermi energies of the first and second electrodes (3, 4) or the Fermi energies established at the first and second electric junctions shift due to the voltage, wherein the energy difference allows the tunneling current to flow between the quantum states (17, 19), wherein electrons tunneling between said first and second quantum states (17, 19) lose energy in the process and generate plasmons at the plasmon supporting surface, wherein the generated plasmons have an energy which corresponds to the energy lost by the tunneling electrons. an electric circuit, a plasmon supporting surface and first and second quantum systems (13, 15) respectively defining first and second quantum states (17, 19) with a tunneling junction being present between the first and second quantum systems (13, 15), the first and second quantum systems (13, 15) being present in the electric circuit to generate a tunneling current between the first and second quantum systems (13, 15), wherein the surface plasmon generator comprises a first electrode associated with the first quantum system and forming part of the electric circuit and a second electrode associated with the second quantum system and forming part of the electric circuit or a first electric junction between the first quantum system and the electric circuit and a second electric junction between the second quantum system and the electric circuit, wherein the quantum states (17, 19) each have an energy close to the Fermi level of their respective associated electrode (2, 5) or respective Fermi energies are established at the first and second electric junctions, whereby the plasmon supporting surface is positioned proximate to at least one of the first quantum system, the second quantum system and the tunneling junction, wherein the electric circuit comprises a voltage source that is configured to provide a voltage between the first electrode or the first electric junction and the second electrode or the second 2. electric junction, wherein the voltage causes a corresponding energy difference between the Fermi level of the first electrode or the Fermi energy established at the first electric junction and the Fermi level of the second electrode or the Fermi energy established at the second electric junction, wherein the energy levels of the first and second quantum states (17, 18) shift in the same way as the Fermi energies of the first and second electrodes (3, 4) or the Fermi energies established at the first and second electric junctions shift due to the voltage, wherein the energy difference allows the tunneling current to flow between the quantum states (17, 19), wherein electrons tunneling between said first and second quantum states (17, 19) lose energy in the process and generate plasmons at the plasmon supporting surface, wherein the generated plasmons have an energy which corresponds to the energy lost by the tunneling electrons.