Product Code: ICA11_C103

Novel Diffractive Beam Splitters with Efficiency Above 95% Enable Multiple Beam Parallel Processing with Highest Throughput
Authors:
Oliver Homburg, LIMO Lissotschenko Mikrooptik GmbH; Dortmund Germany
Yuri Miklyaev, Limo Lissotschenko Mikrooptik Gmbh; Dortmund Germany
Mikhail Ivanenko, Limo Lissotschenko Mikrooptik Gmbh; Dortmund Germany
Vitalij Lissotschenko, Limo Lissotschenko Mikrooptik Gmbh; Dortmund Germany
Presented at ICALEO 2011

In laser-based micro-machining, like high-speed patterning, perforation or dicing frequently the original laser beam is split into several beamlets to increase the throughput of the laser patterning system. Commonly diffractive optical elements with binary or multi-level step-like profiles are used which are produced by etching technique. This method typically results in optical efficiencies about 70-80%. Substantial scattering occurs at the profile steps which also give the tendency to lower damage threshold as compared to intrinsic material values.
In contrast LIMOs unique production technology of programmable continuous free form surfaces on wafer basis is capable to produce kinoform beam splitters with efficiencies > 95%.
We report on various kinds of linear symmetric diffractive beam splitters from 1:3 up to 1:11 at wavelengths between 355 1064 nm. The efficiency for 1:11 splitters is above 95%, the homogeneity between the different beams is typically between +/-2 to 5%. The design data, simulations with the measured surface profiles and experimental intensity measurements will be compared. Finally, the utilization in manufacturing equipment is discussed and demonstrated.