Reflection and/or diffraction based method and setup for generating high energy terahertz pulses

摘要

The present invention relates to a novel technique for generating terahertz radiation. According to the present technology, the pump beam 12 is coupled to an optical element 50 made of a medium having non-linear optical properties having a planar parallel anterior interface 51 and a posterior interface 52, wherein the pump beam ( 12 ) is split into a set of partial pump beams 121 by reflection and/or diffraction on a periodic relief structure 53 formed at the rear interface 52 of the optical element 50 . Partial pump beams in a given medium moving along a direction characterized by an angle γ that satisfies the velocity matching condition of , where v _p;cs is the group velocity of the pump beam, v _㎔;f is the phase velocity of the terahertz radiation, and γ is the pump The angle formed by the pulse shear envelope and phase shear of the beam. The envelope 212 of the pump pulse front segments 221 propagating in the partial pump beams _{travels at a velocity v ㎔; f} of the terahertz radiation 60 towards the front interface 51 of the optical element 50 and It generates terahertz radiation in a nonlinear optical medium through a nonlinear optical interaction.