Patent ID: 9625623
Date: 2017-04-18
CPC Classifications: B23K,G02B

Claim:
1. A beam focuser for focusing an entrance bundle of collimated beams around an optical axis in a focus area around a focal point, the beam focuser comprising: a first axicon disposed inlet side with an axicon angle; a second axicon with the same axicon angle; and an imaging optical system arranged outlet-side and arranged in succession, centered along an optical axis, wherein the first and second axicon are arranged mirror-symmetrically along the optical axis, wherein a focal point of the imaging optical system faces the outlet side of the beam focuser, and wherein on a plane surface of the first axicon and on a plane surface of the second axicon a diffractive optical element is arranged, which transmission function is selected such that a group velocity dispersion and optionally higher-order dispersions of an ultrashort laser pulse are minimized along the beam path by the beam focuser.