Micro-lens arrays are widely used for beam shaping, especially beam homogenization of various laser sources.
Monolithic arrays of cylindrical lenslets made of glass, semiconductors or crystals provide great advantages in laser
applications, e.g. high efficiency, intensity stability and very low absorption. However, up to now, mainly symmetrical
micro-lens surfaces are utilized in most applications due to design and manufacturing restrictions. The manufacture and
application benefits of asymmetrical cylindrical-like micro-lens surfaces are enabled by LIMO's unique production
technology. The asymmetrical shape is defined by uneven-polynomial terms and/or an asymmetrical cut-off from an
even polynomial surface. Advantages of asymmetrical micro-lenses are off-axis light propagation, the correction of
aberration effects or intensity profile deformations when the illuminated surfaces are not orthogonal to the optical axis.
Additionally, the opportunities in simultaneous illumination from numerous light sources to one target are extended by
just geometrical arrangement without the need for collinear beam alignment. First application results of such micro-lens
arrays are presented for beam shaping of high power diode lasers. The generation of a homogeneous light field by a 100
W laser with tilted illumination at an angle of 35° is shown. A multi-kW line generator based on the superposition of
over 50 diode laser bars under different illumination angles is demonstrated as well. Thus, laser material processing like
plastics welding, soldering or annealing becomes much more convenient and less demanding regarding beam steering.