Laser device comprising - a first laser unit capable of emitting a laser beam during operation, propagating in a first direction (x), - at least a second laser unit capable of emitting a laser beam during operation, propagating in a second direction (z), which differs from the first direction (x) and is oriented preferably orthogonally to the first direction (x), as well as - a polarization coupling means, disposed and formed such that it can couple the laser beam of the first laser unit, which is polarised in a first direction, with the laser beam of the second laser unit, which is polarised in a second direction, such that by a collinear superposition of the two laser beams (5, 6), a first resulting laser beam can be obtained, characterised in that the polarisation coupling means is formed as a polarisation coupling prism, comprising a light entry surface through which the laser beam of the first laser unit can enter into the polarisation coupling prism, a reflection surface disposed relative to the light entry surface in such a manner that the laser beam of the first laser unit impinges on the reflecting surface at an angle greater than a critical angle of total internal reflection, anda light exit surface through which the laser beam of the first laser unit can exit from the polarisation coupling prism after the total internal reflection at the reflection surface and can be refracted thereon, and wherein the second laser unit being disposed relative to the polarisation coupling prism in such a manner that the laser beam of the second laser unit can impinge on the light exit surface such that it can be reflected at this in a direction, which corresponds to the propagation direction of the laser beam of the first laser unit refracted at the light exit surface, such that the first resulting laser beam can be obtained by the collinear superposition of the two laser beams (5, 6). - a first laser unit capable of emitting a laser beam during operation, propagating in a first direction (x), - at least a second laser unit capable of emitting a laser beam during operation, propagating in a second direction (z), which differs from the first direction (x) and is oriented preferably orthogonally to the first direction (x), as well as - a polarization coupling means, disposed and formed such that it can couple the laser beam of the first laser unit, which is polarised in a first direction, with the laser beam of the second laser unit, which is polarised in a second direction, such that by a collinear superposition of the two laser beams (5, 6), a first resulting laser beam can be obtained, characterised in that the polarisation coupling means is formed as a polarisation coupling prism, comprising a light entry surface through which the laser beam of the first laser unit can enter into the polarisation coupling prism, a reflection surface disposed relative to the light entry surface in such a manner that the laser beam of the first laser unit impinges on the reflecting surface at an angle greater than a critical angle of total internal reflection, anda light exit surface through which the laser beam of the first laser unit can exit from the polarisation coupling prism after the total internal reflection at the reflection surface and can be refracted thereon, and wherein the second laser unit being disposed relative to the polarisation coupling prism in such a manner that the laser beam of the second laser unit can impinge on the light exit surface such that it can be reflected at this in a direction, which corresponds to the propagation direction of the laser beam of the first laser unit refracted at the light exit surface, such that the first resulting laser beam can be obtained by the collinear superposition of the two laser beams (5, 6).