基于光栅外腔的高功率半导体激光阵列谱合束研究进展

半导体激光器与其他类型激光器相比具有寿命长、效率高和波长范围广等优点，使其成为现代激光领域的重要组成部分。输出功率和光束质量是判断半导体激光器优劣的两大关键指标，但半导体激光器的特殊原理和结构决定了它在追求高功率的同时光束质量会劣化，导致其应用范围受限。谱合束技术被证明是解决该问题的关键技术之一，但目前仍然存在光功率和光束质量退化等问题；因此，如何获得高亮度合成光束成为国内外研究热点。针对外腔谱合束技术，本文首先介绍了半导体激光阵列和叠阵，总结比较了应用于谱合束技术的3类光栅，阐述了光栅外腔法谱合束技术的基本原理，概括了国内外高功率半导体激光阵列谱合成技术的研究进展和现状，分析讨论了导致合成光束质量劣化和合束功率耗损的因素，展望了高亮度半导体激光器的发展前景。本研究有助于推动高亮度半导体激光器直接光源的进一步发展。

Progress on Spectral Beam Combining Technique of High-power Diode Laser Array by Grating-external Cavity

Diode lasers’ advantages, such as long operation life, high electro-optical efficiency and selectable wavelength, make the diode laser be an important part of modern laser field. The output power and beam quality are two key parameters to evaluate the performance of diode lasers. Due to the special structure of diode lasers, the beam quality degrades obviously with the increasing power, which limits diode lasers to be employed as a direct light source. The spectral beam combining technology has been proven to be an effective way to achieve beams with both high power and good beam quality. However, in practical spectral beam combining system, the power and beam quality of combined beams still have a non-negligible degradation, and the issue of how to get beams with high-brightness has been attracting the attention of an increasing number of researchers. In this paper, the diode laser array/stack is introduced briefly, and three kinds of gratings employed in spectral beam combining system are analyzed. The spectral beam combining technique by grating-external cavity is described in detail, and then the development of spectral beam combining technique of high-power diode laser array is briefly reviewed. Factors which make the beam quality deteriorate and the combining power degrade are analyzed in detail. Finally, the future development of high-brightness diode lasers is prospected. This work is expected to promote the further development of spectral beam combining technique by grating-external cavity.