Patent ID: 8759771

Claim:
An optical device arranged to generate or detect a terahertz wave, the optical device comprising: a laser light source configured to output light; an optical element configured to generate or detect the terahertz wave when the optical element is irradiated with the light; and an optical unit configured to direct the light from the laser light source to the optical element, wherein the optical element includes: a semiconductor layer; and a plurality of electrodes formed in electrical contact with the semiconductor layer and including an antenna configured to couple the terahertz wave and a space, wherein at least one of the electrodes forms a Schottky junction between the one electrode and the semiconductor layer; wherein the laser light source outputs the light whose photon energy is larger than a barrier height of the Schottky junction and smaller than an energy band gap of the semiconductor layer; and wherein the optical unit is arranged to irradiate the Schottky junction with the light through a surface of the semiconductor layer without the electrodes.