Anamorphic beam shaping for efficient laser homogenization: methods and high power applications

Abstract

The homogenization of light is widely applied in various industrial sectors. The uniform high power processing of large areas requires a high degree of homogeneity. Sophisticated beam transformation techniques are used to optimize the illumination of standard optical diffusers such as microlens arrays and decrease the contrast of interference. Novel design techniques take advantage of a multimodal approach which is especially adapted to the characteristic properties of the laser light source. We show how anamorphic beam shaping is employed to transform the high power light source in order to meet the required level of homogeneity suited for the respective application.

Dynamic coherent beam combining based on a setup of microlens arrays

“…This offers a new possibility for scientific and industrial applications such as material processing. [6][7][8][9][10] A CBC system is an interferometer with amplifiers in the interferometer arms. The pulses of the common seed source are subsequently split and sent into the interferometer arms, amplified and combined into a single output beam.…”

“…These elements are often used for beam homogenization. 8,17 In a few publications it is described that spatially coherent or nearly spatially coherent light sources cannot be homogenized sufficiently with microlens arrays. 18,19 With spatially coherent light a spot pattern is generated caused by grating diffraction and interference.…”

Advanced industrial laser systems and applications

“…Consequently, applications such as tempering of multi-functional coatings, a lift-off process of thin layers from substrates used for the production of OLEDs 29 or solid-state laser annealing of silicon for semiconductor manufacturing become feasible. 30,31 For the latter, the laser beam induced melting and solidification of thin silicon films is used to attain a semi-crystalline grain structure of high uniformity as required for high-resolution thin-film transistor (TFT) displays with increased performance of the driver electronics for the pixelsas depicted in Figure 20. 32 The optical concept of TRUMPF's line beam optics as schematically depicted in Figure 21 is unique with respect to its beam transformation and beam shaping technique, its efficiency and compactness and its multi-kW operational powerlevel.…”

“…It provides reduced complexity, since the total number of modules is low compared to free-beam approaches. 31…”

Focal field analysis of highly multi-mode fiber beams based on modal decomposition

“…For this purpose, a numerical approach is presented here that evaluates intensity profiles taken from standardized caustic measurements. The determination of the modal power spectrum of a highly multi-mode fiber contributes not only to the exact focal field analysis required for beam shaping [17], but also to research fields such as fiber characterization, imaging technologies [18][19][20] and optical communication [21]. The paper is organized as follows.…”