Diode laser modules of highest brilliance for materials processing

Alexander Knitsch; Axel Luft; Tobias Gross; Detlev Ristau; Peter Loosen; Reinhart Poprawe

doi:10.1117/12.467954

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22 May 2002 Diode laser modules of highest brilliance for materials processing

Alexander Knitsch, Axel Luft, Tobias Gross, Detlev Ristau, Peter Loosen, Reinhart Poprawe

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Proceedings Volume 4651, Novel In-Plane Semiconductor Lasers; (2002) https://doi.org/10.1117/12.467954
Event: Symposium on Integrated Optoelectronic Devices, 2002, San Jose, California, United States

Abstract

Beam quality and output power of mostly 2-dimensional stacked diode laser systems are insufficient for the demands of materials processing. To increase the output power at almost constant beam-quality, superimposition of diode laser bars of different wavelengths as well as polarization-multiplexing of s- and p-polarized laser beams is possible. Different techniques for wavelength-multiplexing have been developed. The so-called multi-filter concept of a spanned coated etalon with edge-filters has turned out best. The concept features a modular design, simple adjustment and easy add-on of more wavelengths. Concerning the polarization-multiplexing we take advantage of the almost linear polarized diode laser bars. Ordinary used beam splitter cubes with a cemented structure are less qualified for high radiance. Hence the beam combination is achieved with beam displacers made of a birefringent crystal (YVO₄) which provide high transmittance and convenient adaptation. Finally an experimental set-up with 8 diode laser bars of 4 different wavelengths, i.e. 8-times beam superimposition, is realized. The set-up called multiplexer obtains a radiance of about 4 x 10⁶ W cm^-2 sr^-1 and outnumbers all other comparable high power diode laser systems.

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Alexander Knitsch, Axel Luft, Tobias Gross, Detlev Ristau, Peter Loosen, and Reinhart Poprawe "Diode laser modules of highest brilliance for materials processing", Proc. SPIE 4651, Novel In-Plane Semiconductor Lasers, (22 May 2002); https://doi.org/10.1117/12.467954

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