OPTICAL ELEMENT

PROBLEM TO BE SOLVED: To provide an optical element of type irradiating light to a Schottky junction part to generate or to detect the terahertz wave and improving the generation efficiency and detection efficiency of the terahertz wave. SOLUTION: The optical element includes a semiconductor layer 2 having an energy bandgap larger than that of a photon energy of light and a plurality of electrodes 3 electrically contacting with the semiconductor layer 2. At least one of the electrodes 3 forms a Schottky junction having a barrier height not more than that of the photon energy of the light 6 between the electrode and the semiconductor layer 2. At least a part of the junction face between the electrodes 3 forming the Schottky junction and the semiconductor layer 2 includes a light irradiation face to which the light 3 is irradiated from the face side of the semiconductor layer 2 to which no electrode 3 is formed, and is a component part of a coupling structure coupled with terahertz wave 7 generated or detected by the irradiation of the light 3. COPYRIGHT: (C)2011,JPO&INPIT