Patent ID: 8003961

Claim:
An electromagnetic wave generating device, comprising: a carrier generation layer for generating a carrier by light irradiation; a first electrode provided on the carrier generation layer for applying voltage to the carrier generation layer; a reference electrode provided on the carrier generation layer for defining a reference potential of the first electrode; and a transmission line for propagating a terahertz wave generated based on the carrier generated in the carrier generation layer, the transmission line being formed so as to include the first electrode, wherein: the transmission line includes: a first region in which the terahertz wave propagates in a first direction; and a second region having an impedance different from an impedance of the first region and forming a reflection interface with respect to a terahertz wave which propagates in a direction opposite to the first direction; and a distance from an irradiation location at which light is irradiated to the carrier generation layer to the reflection interface is set to be smaller than D, where D is a distance converted from a half width of a time waveform of the terahertz wave which propagates in the first direction without passing through the reflection interface.