Joule-Class 940-nm Diode Laser Bars for Millisecond Pulse Applications

P. Crump1, C. Frevert1, A. Ginolas1, S. Knigge1, A. Maaßdorf1, J. Lotz2, W. Fassbender2, J. Neukum2, J. Körner3, T. Töpfer3, A. Pranovich4, M. Divoky4, A. Lucianetti4, T. Mocek4, K. Ertel5, M. De Vido5, G. Erbert1, and G. Tränkle1

Published in:

IEEE Photonics Technol. Lett., vol. 27, no. 15, pp. 1663-1666 (2015).

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Abstract:

The use of long resonators (for improved thermal and electrical resistance) and advanced facet passivation (for high power) is shown to enable Joule-class pulse emission from single passively cooled 1-cm diode laser bars emitting at 940 nm. Bars on CS-mount deliver pulse energy of 1 J at 60% power conversion efficiency within a 7-nm spectral window, under quasi-continuous wave conditions (1.2 ms 10 Hz). Robustness of device performance is confirmed via burn-in and multisite testing. Joule-per-bar performance is also maintained for conduction cooled monolithic stacked arrays, adapted for bars with long resonators. Although these packages only cool the laser bar via their rear edge, peak power, lateral far field, and spectral width remain consistent with the requirements for pumping solid state lasers and scale as predicted with self-heating. An energy density >10 J/cm2 is delivered from the stack surface, for brightness >3 MW/(cm2-sr).

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
2 DILAS GmbH, 55129 Mainz, Germany
3 Lastronics GmbH, 07745 Jena, Germany
4 HiLASE Centre, Institute of Physics ASCR, v.v.i., 25241 Dolní Brecany, Czech Republic
5 STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.

Index Terms:

Semiconductor laser arrays, power conversion, pulse power systems, pumps, YAG lasers, cryogenics.