ASTIGMATIC GRADIENT-INDEX ELEMENTS FOR LASER-DIODE COLLIMATION AND BEAM SHAPING

For the conversion of light from edge-emitting laser diodes into symme tric laser beams two main tasks have to be performed: collimation and beam shaping. Generally these two jobs are performed separately. Becau se of the inherently different divergence angles of the emitted light, collimation with astigmatic lenses generally results in a beam with a n elliptically shaped amplitude distribution. This asymmetry has to be compensated for by an anamorphic imaging step to obtain the desired s pherical beam profile. It can be advantageous to combine both jobs in one element. We demonstrate the design, the fabrication, and the appli cation of refractive gradient-index elements, which allow one to perfo rm both jobs with a single element. Our astigmatic lenses were fabrica ted by silver-sodium ion exchange in glass.