Patent ID: 8497490

Claim:
A terahertz wave generation device for generating terahertz waves in a direction satisfying non-collinear phase matching conditions by projecting ultra-short pulse laser light on a non-linear optical crystal, the terahertz wave generation device comprising: a pulse light source for generating the ultra-short pulse laser light; and an irradiation unit for discretely irradiating the ultra-short pulse laser light generated by the pulse light source on terahertz wave transmission line in the non-linear optical crystal so that the ultra-short pulse laser light is in synchronous with transmission of the terahertz wave; wherein the irradiation unit comprises a plurality of optical fibers for receiving and transmitting the ultra-short pulse laser light generated by the pulse light source and projecting such toward the terahertz wave transmission line of the non-linear optical crystal so that the ultra-short pulse laser light is in synchronous with transmission of the terahertz wave; the optical fibers have mutually differing optical path lengths; the irradiation unit further comprises a light distributor for splitting the ultra-short pulse laser light generated by the pulse light source into a plurality of ultra-short pulse laser lights and transmitting such to the plurality of optical fibers; the irradiation unit further comprises a length adjustment mechanism for adjusting the optical path lengths of the optical fibers; and the length adjustment mechanism comprises drums around which the optical fibers are wound, and a tension changing unit for changing the tension of the optical fibers in a lengthwise direction by changing the diameter of the drums.