Beam shaping unit for focusing a laser beam

A beam shaping unit for focusing a divergent laser beam onto a workpiece, the beam shaping unit comprising:

• a first optical element to receive the divergent laser beam;
• a second optical element arranged downstream of the first optical element to receive the laser beam from the first optical element;
• an optical focusing unit arranged downstream of the second optical element to receive the laser beam from the second optical element;
• a first focal point adjustment device coupled to the first optical element, wherein the first focal point adjustment device is configured to adjust a focal point diameter (D) of the laser beam by manipulating the first optical element;
• a second focal point adjustment device coupled to the second optical element, wherein the second focal point adjustment device is configured to adjust, in a propagation direction of the laser beam, a focal position of the laser beam by manipulating the second optical element, wherein the laser beam is imaged by the first optical element through an intermediate focal point onto the second optical element;
• an additional optical unit arranged downstream of the optical focusing unit in the propagation direction of the beam, wherein the additional optical unit seals the beam shaping unit against gas pressure;
• and
• a housing, wherein a portion of a wall of the housing is partitioned between the optical focusing unit and the additional optical unit, and wherein a region in which the partition is located is covered by a resilient bellows.