Multiple double-metal bias-free terahertz emitters
  We demonstrate multiplexed terahertz emitters that exhibits 2 THz bandwidth that do not require an external bias. The emitters operate under uniform illumination eliminating the need for a micro-lens array and are fabricated with periodic Au and Pb structures on GaAs. Terahertz emission originates from the lateral photo-Dember effect and from the different Schottky barrier heights of the chosen metal pair. We characterize the emitters and determine that most terahertz emission at 300 K is due to band-bending due to the Schottky barrier of the metal. 
Duncan McBryde, Paul Gow, Sam A. Berry, Armen Aghajani, Mark E.   Barnes, V. Apostolopoulos
physics.optics