Lithuanian patent “Broadband high-frequency generating / amplifying device, using semiconductor superlattices” by Gintaras Valušis, Kirill Alekseev, Vladislovas Čižas, Linas Minkevičius, Natalia Alexxeva, Dalius Seliuta, Liudvikas Subačius.

New principle and at the same time a new type of compact high-frequency radiation source operating at room temperature that can be placed on a semiconductor chip is suggested. It is broadband and can operate in the both GHz and THz frequency bands. Operation of the device relies on principles of the quantum optoelectronics (Esaki-Tsu nonlinearity of the quantum super-lattice), and employ drift-relaxation modes to amplify high-frequency radiation, which propagates in a semiconductor superlattice along its axis at a speed approximately 1000 times slower than the speed of light in a material. It can be realized in semiconductor superlattice with non-ohmic injection contacts of an appropriate design.