BEAM FORMATION UNIT COMPRISING TWO AXICON LENSES, AND DEVICE COMPRISING ONE SUCH BEAM FORMATION UNIT FOR INTRODUCING RADIATION ENERGY INTO A WORKPIECE CONSISTING OF A WEAKLY-ABSORBENT MATERIAL

摘要

The invention relates to a beam formation unit (4) for producing a ray beam which is focussed in a punctiform manner, diverges in an annular manner, and has a radiation-free central region, said unit consisting of a focussing lens (2), a first axicon (1), and a second axicon (3). The invention also relates to a device comprising one such beam formation unit (4) for introducing radiation energy into a workpiece (14) which consists of weakly-absorbent material and is arranged between a first resonator mirror (13) and a second resonator mirror (19), the first resonator mirror (13) arranged upstream of the workpiece (14) in the direction of radiation being located in the radiation-free central region. The radiation energy can be absorbed to a maximum by penetrating the same interaction volume in the workpiece (14) several times.