Patent ID: 8759779

Claim:
A terahertz wave generation element comprising: a plurality of waveguides including an electro-optic crystal; and an optical coupling member configured to extract a terahertz wave to the outside, the terahertz wave being generated when light propagates through the waveguides, wherein the waveguides are arranged to be rotationally symmetric with respect to a predetermined axis; the optical coupling member is arranged so that wave fronts of the terahertz waves generated from the waveguides are matched together, and an angles between the predetermined axis and a terahertz wave emitting surface of the optical coupling member is represented by the following formula: tan θ A =( n 0 /n clad −cos(θ p −θ c ))/sin(θ p −θ c ) here, θ p : an angle between a light propagation direction in the waveguide and the predetermined axis, θ c : an angle between the light propagation direction in the waveguide and the terahertz wave emitted from the waveguide, n clad : a refractive index of the optical coupling member at a wavelength of the terahertz wave, and n 0 : a refractive index at a portion in contact with the optical coupling member on the terahertz wave emitting surface.