高损伤阈值半导体激光腔面介质膜制备与检测技术研究

The reason of the widely used is the high output power and long term reliability of high power semiconductor lasers, and the facet catastrophic optical damage(COD) has been the key factor of the output power and reliability of lasers. By the technology of Electron paramagnetic resonance(EPR), Scanning electron microscope(SEM) and Cathodoluminescence(CL), the defects and surface states on the lasers facets was investigated. And by plasma surface treatment technology the surface states on the lasers facets was removed. Then non-absorption window was fabricated on the lasers facets. By plasma ion assisted deposition technique the elements of the dielectric film, the density of impurities and defects, the stress model and levels were controled. By SEM, SIMS, EPR, XRD and other methods the microstructure and properties of films were characterized. Based on this test by SPTS laser heat absorption test technology and online real-time monitoring method of the microscopic image, the mechanism of film and laser interaction and the transient behavior of film damage was investigated. The mechanism and kinetics of film damage was explored. Through the above study and the internal relations of film properties and the facet catastrophic optical damage and the damage principle of dielectric film on the lasers facet were mastered. By improved technology and methods of film preparation, developing the COD of the lasers facet is higher than 5 MW/cm2 and reflectance of the dielectric film is more than 99.9%. The 915nm single bar of quasi-continuous output 10W and 808nm laser bar of continuous output 60W were developed.

高输出功率和长期可靠性是大功率半导体激光器得以广泛应用的前提，而腔面灾变性光学损伤阈值一直是限制其最大输出功率和可靠性的重要因素。本项目采用SEM+CL和EPR技术对激光器腔面的缺陷和表面态进行研究，并采用等离子表面处理技术去除腔面表面态，再在腔面制作激光的非吸收窗口。采用离子辅助镀膜技术控制介质膜的元素比、杂质与缺陷的密度、应力模式与水平，再利用SEM、SIMS、EPR、XRD等方法对薄膜的微观结构和特性进行表征。在此基础上利用SPTS激光热吸收测试技术与在线显微图像实时监视法对薄膜与激光相互作用的物理过程及薄膜损伤的瞬态行为进行研究，探索薄膜损伤的机理及动力学过程。 通过以上研究掌握薄膜激光损伤与薄膜特性的内在联系，改进薄膜制备工艺及方法，研制出损伤阈值高于5MW/cm2、反射率大于99.9%的介质膜，研制出915nm准连续输出10W的单管芯片和808nm连续输出60W的激光Bar条。

大功率半导体激光器具有全固态、体积小、重量轻、寿命长、效率高等特点，它是全固态激光器的理想泵浦光源，是光纤激光器的重要泵浦光源；在国防、材料加工、医疗、显示等领域获得广泛应用。高输出功率和长期可靠性是大功率半导体激光器得以广泛应用的前提，而半导体激光器的腔面灾变性光学损伤（COD）阈值一直是限制其最大输出功率和可靠性的重要因素。目前国外半导体激光灾变性光学损伤阈值的研究水平为30MW/cm2，产品水平10～20MW/cm2，但其技术细节已成为一种商业机密，在相关文献中并没有做详细报道；而国内的相关研究与国外先进水平的差距较大，只有几个兆瓦,因此研究半导体激光器腔面介质薄膜的损伤机理，掌握薄膜与激光相互作用的物理过程及薄膜损伤的瞬态行为，制备高激光损伤阈值腔面光学薄膜，已成为高功率半导体激光器在国防应用领域必须突破的一项关键技术。.本项目开展了介质薄膜的吸收损耗、薄膜应力释放机制及薄膜应力的控制技术研究、介质膜损伤过程监测技术研究；开展了超高反射率介质薄膜的制备及薄膜稳定性研究和半导体激光腔面超低反射介质膜的制备技术研究；开展了等离子表面处理技术、离子辅助沉积镀膜技术与非吸收窗口技术研究。通过谐振腔结构和腔面介质薄膜结构的优化设计、半导体激光器腔面微观结构的改善，具有非吸收窗口结构的衬底层的制备，研制出915nm准连续输出10.9W的半导体单管芯片（W=105μm、Period 450μm、L=4.0mm），灾变性光学损伤阈值达到5.19MW/cm2，达到国内报道最佳水平。该技术可提高器件的输出功率和可靠性，降低半导体激光模块成本和体积，满足国防和工业需求。同时研制出808nm连续输出61.75W的激光Bar条芯片；开发出反射率大于99.99%的高反射介质薄膜，反射率小于0.1%的670nm和740nm超低反射腔面膜用于外腔窄线宽激光器。