Narrower Far Field and Higher Efficiency in 1 kW Diode-Laser Bars Using Improved Lateral Structuring

M.M. Karow, D. Martin, P. Della Casa, G. Erbert, and P. Crump

Published in:

Conf. on Lasers and Electro-Optics/Europe and European Quantum Electronics Conf. (CLEO/Europe-EQEC 2019), Munich, Germany, Jun. 23-27, ISBN: 978-1-7281-0469-0, cb-5.4 (2019).

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High power, efficient diode-laser bars with narrow far field angles are sought for many applications, for example in the 9xx nm-range for the pumping of Yb:YAG disc and slab lasers [1,2]. In previous work, broad-area (BA) diode-laser bars with 4 mm resonator length operated with high conversion efficiency η = 62% at operating power P op = 1 kW in quasi-continuous wave testing (200 µs, 10 Hz), by using low optical loss and low-resistivity vertical structures and high fill-factors (∼70%) [1]. Lateral far field (95% power) was Θ 95 % > 10° [2]. However, higher η and narrower Θ 95 % are needed for industrial application, and we seek improvements by altering the lateral bar structure for a fixed vertical design (from [1], wavelength λ = 930 nm, loss α i ≤ 0.4 cm-1).

Ferdinand-Braun-Institut, Leibniz Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany