The invention relates to a radiation source, comprising at least one semiconductor substrate, on which at least two field-effect transistors are formed, which each contain a gate electrode, a source contact, and a drain contact, which bound a channel, wherein the at least two field-effect transistors are arranged adjacent to each other on the substrate, wherein each field-effect transistor has exactly one gate electrode and at least one source contact and/or at least one drain contact is arranged between two adjacent gate electrodes, wherein a ballistic electron transport can be formed in the channel during operation of the radiation source. The invention further relates to a method for producing electromagnetic radiation having a vacuum wavelength between approximately 10 μm and approximately 1 mm.