Patent ID: 7177071

Claim:
A terahertz wave-generating semiconductor crystal, comprising a zincblende-type III-V compound semiconductor crystal that generates terahertz wave pulses upon application of an ultrashort light pulse in the optical communication band serving as a pump beam, wherein the zincblende-type III-V compound semiconductor crystal is one selected from the group consisting of GaAs, InGaAs, InGaAsP, InAlAs, InP, GaP, GaSb, and AlSb crystals, the zincblende-type III-V compound semiconductor crystal is a quasi-phase matching crystal, and the quasi-phase matching crystal comprises layers of a first semiconductor crystal and a second semiconductor crystal alternately stacked on each other, the first semiconductor crystal having a group index at the wavelength of the pump beam greater than the refractive index at the wavelength of the terahertz waves, the second semiconductor crystal having a group index at the wavelength of the pump beam smaller than the refractive index at the wavelength of the terahertz waves.