High cw power using an external cavity for spectral beam combining of diode laser-bar emission

Abstract

In extension to known concepts of wavelength-multiplexing diode laser arrays, a new external cavity is presented. The setup simultaneously improves the beam quality of each single emitter of a standard 25 emitter broad-area stripe laser bar and spectrally superimposes the 25 beams into one. By using this external resonator in an "off-axis" arrangement, beam qualities of Mslow2<14 and Mfast2<3 with optical powers in excess of 10 W in cw operation are obtained.

Spectral beam combining of a 980 nm tapered diode laser bar

“…Off-axis spectral beam combining is a relatively new technique which has also been used for improving the slow axis beam quality of broad area diode laser bars. Jechow et al [7], has used an external cavity in an off-axis arrangement for spectral beam combining of a broad area laser bar and achieved a beam with M 2 slow < 14 and M 2 fast < 3 at an optical power in excess of 10 W. Moreover, Jensen et al [8], has used off-axis spectral beam combining on a segmented broad area diode laser and achieved an improvement in the beam quality of a factor of 3.4 compared to that of a freely running single emitter on the array. Recently, Vijayakumar et al [9], applied this technique on a 12 element broad area diode laser bar and achieved an improvement in beam quality of a factor of 5-6 to that of a free running emitter on the same bar.…”

980 nm high brightness external cavity broad area diode laser bar

“…In 2006, Jensen et al, [10] applied off-axis spectral beam combining to a segmented broad area laser diode and achieved a beam quality improvement of a factor of 3.4 compared to a single free running segment. In 2006, Jechow et al, [11] used an external cavity in an off-axis arrangement for spectral beam combining of a broad area laser bar and achieved a beam with M 2 slow < 14 and M 2 fast < 3 at an optical power in excess of 10 W. In this paper, we report on off-axis spectral beam combining applied to a 980 nm high power diode laser bar. We applied off-axis feedback to 12 broad area emitters, which resulted in a 5-6 fold improvement in the beam quality along the slow axis of the output beam compared to a free running single emitter on the same laser bar.…”

Development of Spectral Beam Combining of Diode Laser by Grating and External Cavity

“…Schematic of SBC with external cavity feedback based on grating 由图 1 可见， 光谱合束装置是由半导体激光器阵列(DLA)、 快轴准直镜(FAC)、 慢轴准直镜(SAC)变换柱 透镜、 光栅与外腔镜组成。半导体激光器的大发散角， 会严重限制了半导体激光器阵列和叠阵的光谱合束， 原因在于慢轴光束的发散， 使得每个阵列单元之间形成交叉耦合， 这种交叉耦合导致多旁瓣输出 [10] [12] 国波茨坦大学和丹麦技术大学提出了一种基于离轴反馈的光谱合束方法 [16][17] 2009 年丹麦技术大学 Vijayakumar [18] 等利用图 7(a)所示的旁轴反馈对高功率宽发射面半导体激光器线…”