PFI-TT: Reliable High-Power Circular-Beam Semiconductor Lasers

该创新-技术转化合作伙伴关系（PFI-TT）项目的更广泛影响/商业潜力是展示了一种新型可靠的高光束质量半导体激光器，能够产生圆形的、近乎理想的输出激光束，其功率范围是现有技术在不使用外部系统的情况下无法达到的。以低得多的成本提供更高质量、近乎完美的激光束有望实现有益于社会的新应用：更快的数据网络、创新的医疗保健解决方案、增强的自动驾驶汽车安全性和改进的消费产品。这将通过消除包含额外光束退化的外部光学组件来实现。 这些进步是由于更容易操纵和聚焦的光束产生更强烈的激光聚焦点。 所采用的新处理方法还将为提高未来光子集成电路的密度带来显著的额外前景，这对于支持社会对互联网和数据中心应用的快速增长的需求至关重要。拟议的项目专门解决了大多数边发射二极管激光器的长期局限性-它们固有的不对称，高度椭圆，从而在10-500 mW范围内产生衍射（难以聚焦）输出光束。像垂直腔表面发射激光器（VCSEL）这样的设备可以发射圆形输出光束，但限于约5-10 mW的最大输出功率。 所提出的创新使用一种新的方法来制造边发射激光器，采用深蚀刻通过有源电子空穴复合区，然后通过特殊的湿热氧化工艺来改善蚀刻损伤，同时平滑和钝化蚀刻的侧壁。利用这种高折射率对比度设计，已经实现了功率比商业单模VCSEL大80倍的单模圆形输出激光器。该项目的重点是对带有端面钝化涂层的封装激光器进行寿命测试，并证明其长寿命、连续运行的能力（例如，5000-10000小时），以实现成功的商业化。氧化物-半导体界面特性将使用时间分辨光致发光进行评估和优化;包括像散在内的光束质量将被表征，并评估预期的高速RF调制性能。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project is the demonstration of a new class of reliable, high-beam-quality semiconductor lasers capable of producing a circular, nearly ideal output laser beam operating in a power range which is currently inaccessible by existing technologies without the use of external systems. Providing a higher quality, near perfect laser beam at much lower cost promises to enable new applications beneficial to society: faster data networks, innovative healthcare solutions, enhanced autonomous vehicle safety, and improved consumer products. This will be achieved by eliminating external optical components which incorporate additional beam degradation. These advances result from the more-easily manipulatable and focusable beam producing a more intense, laser focused spot. The new processing methods employed will also have significant additional promise for increasing the density of future photonic integrated circuits, critical for supporting society’s rapidly growing needs for internet and data center applications.The proposed project specifically addresses a long-standing limitation of most edge-emitting diode lasers – their inherently asymmetric, highly elliptical, and thus astigmatic (hard to focus) output beams in 10-500 mW range. Devices like vertical cavity surface emitting laser (VCSEL) can emit a circular output beam, but are limited to maximum output powers of ~5-10 mW. The proposed innovation uses a novel method to fabricate edge-emitting lasers, employing a deep etch through the active electron-hole recombination region followed by a special wet thermal oxidation process to ameliorate etch damage while smoothing and passivating the etched sidewall. With this high-index-contrast design, single-mode circular output lasers with powers 80 times greater than that of commercial single-mode VCSELs have been achieved. The focus of this project is to lifetest packaged lasers with facet passivation coatings and demonstrate their capability for long-life, continuous operation (e.g., 5000-10000 hours) as required for successful commercialization. The oxide-semiconductor interface properties will be assessed and optimized using time-resolved photoluminescence; beam quality including astigmatism will be characterized, and the expected high-speed RF modulation performance evaluated. Alternative approaches including quantum-dot active region material and atomic layer deposition dielectrics will also be explored.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.