METHOD TO GENERATE TERAHERTZ RADIATION AND TERAHERTZ RADIATION SOURCE

The present invention relates to a method for generating terahertz radiation, wherein a pump pulse is subjected to pulse front tilting, the thus obtained pump pulse having tilted pulse front is coupled into a nonlinear optical medium and THz pulse is generated by means of the optical medium in nonlinear optical processes, particularly by means of optical rectification by the pump pulse. The invention also relates to a terahertz radiation source (100), comprising a pump source (10) for emitting a pump pulse and a nonlinear optical medium for generating THz pulse. The pump source (10) and the nonlinear optical medium define together a light path, said light path is arranged to guide the pump pulse from the pump source (10) to the nonlinear optical medium. A first optical element (20) having angular-dispersion-inducing property and an imaging optics (30) are disposed in the light path after each other in the propagation direction of the pump pulse. The core of the method according to the invention is that the pulse front tilt of the pump pulse required to satisfy velocity matching condition of v cos(/) = vTHrf is induced as a sum of a plurality of pulse front tilts, each pulse front tilt is induced separately as a partial pulse front tilt of the pump pulse in subsequent steps, wherein vp;cs is the group velocity of the pump pulse, vr¾/is the phase velocity of the THz pulse, and γ is the angle formed between the pulse front and the phase front of said pump pulse. The radiation source (100) according to the invention also comprises at least one further optical element with angular-dispersion-inducing property is provided within said light path, said further optical element located after both the first optical element (20) having angular-dispersion-inducing property and the imaging optics (30) in the propagation direction of said pump pulse. La présente invention a trait à un procédé permettant de générer un rayonnement térahertz. Une impulsion de pompage est soumise à une inclinaison de front d'impulsion, l'impulsion de pompage ainsi obtenue ayant un front d'impulsion incliné est couplée dans un milieu optique non linéaire, et une impulsion THz est générée au moyen du milieu optique lors de processus optiques non linéaires, en particulier au moyen d'une rectification optique par l'impulsion de pompage. La présente invention concerne également une source de rayonnement térahertz (100) qui comprend une source de pompage (10) servant à émettre une impulsion de pom