The present invention has to do with an arrangement for geometric reshaping of a radiation field, especially a radiation field of a diode laser array. This field propagates in a z-direction. It has a radiation cross section, which in one direction defined as the x-direction, runs perpendicular to the z-direction, a direction which is perpendicular to it, defined as the y-direction, exhibiting a greater propagation with lower beam quality. In this case, x, y and z form a rectangular (Cartesian) coordinate system, whereby the radiation is or will be grouped into radiation components in the x-direction. The radiation components, in relation to their beam cross sections, are reoriented. This arrangement includes at least two reflectors.
Such an arrangement is generally known.
There are several areas in such arrangements as are presented above are applied. Among other things, they include geometric reshaping of diode laser outputs, in order to build up defined radiation fields. Additionally, the applications include reshaping of a rectangular radiation field of a laser with an amplification medium having such shapes as slabs or rods. This is done in order to homogenize the beam quality over the cross section of the beam, and to adapt it to specific applications.
High-performance diode laser arrays or field arrangements typically have active media with a cross section of 1 .mu.m.times.10 mm. Because of this, the diode laser radiation is characterized, among other things, by a typically elliptical beam cross section and a large divergence angle in the fast relatively small divergence in the slow direction (parallel to the PN transition).
Such a diode laser array with a beam cross section of 1 .mu.m .times.10 mm possesses extremely varied beam qualities in the two directions parallel and perpendicular to the PN transition. The beam quality in the fast direction is diffraction limited, an ca. 1000 to 2000 times as diffraction limited in the slow direction. For this reason, radiation emitted from a diode laser array cannot be focused by cylindrical and spherical lenses onto a small and circular spot. For this reason, applications of high-performance diode lasers to individual areas are limited, where only small intensities per surface unit are necessary. Expansion of applications to areas such as medical technology and materials processing, fiber coupling and end-on pumping of solid state lasers and fiber lasers, require that the beam quality be homogenized in both directions.
USPTO Backgrounds
USPTO Backgrounds