OPTICAL SYSTEM FOR INCREASING CONTRAST OF PULSED LASER RADIATION, LASER SYSTEM AND METHOD FOR INCREASING CONTRAST OF PULSED LASER RADIATION

摘要

The invention relates to an optical system (3) for increasing contrast of pulsed laser radiation (9) using a non-linear eliptical polarisation rotation, comprising: a first polarisation adjustment lens (19) for adjusting an elliptical polarisation state (17B) of the pulsed laser radiation (9); a multipass cell (5) comprising two opposing mirrors (25A, 25B), forming a concentric resonator, which is passed through multiple times by the pulsed laser radiation (9) forming a plurality of intermediate focus zones (29), wherein the multipass cell (5) is filled with a gas (5A), which has an optical non-linearity, which brings about an intensity-dependent rotation of an orientation of the eliptical polarisation state (17B) of the pulsed laser radiation (9), such that the multipass cell (5) outputs beam parts with differently orientated elliptical polarisation states on the basis of the intensity-dependent rotation; and an optical beam splitting system (41) for splitting the beam parts with differently orientated elliptical polarisation states.