Development of Crystal Furnace to Produce Large Single Crystal Nd:YAG Slabs for High Power Industrial Laser Systems

开发用于高功率工业激光系统的大型单晶 Nd:YAG 板条的晶体炉

• 批准号: 9413860
• 负责人: Bruce Chai
• 金额: $ 49.97万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1997-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9413860&HistoricalAwards=false
• 关键词: Development; Crystal; Furnace; Produce; Large

9413860 Chai Current U.S. sheet metal (especially auto) industries have the need of high power and high repetition rate lasers which are deliverable via optical fibers and linked to robotic arms for high speed and high precision drilling, cutting and welding processes. While both the power supply and optical delivery system are available now, the heart of the laser system, the lasing medium, is still missing. The lasing medium is a large single crystal Nd:YAG slab which produces the laser power under either coherent (laser diode) or incoherent (flash lamp) pumping. Current state-of-the-art growth process is limited to a maximum of 25x200x10mm3 slab due to intrinsic core defects in melt pulled single crystals. Lasers based on slab configuration can generate more power with simpler design and better efficiency. It fits well with current diode array pumping design. We propose construct a novel crystal growth system to grow such Nd:YAG slabs. The system is designed and will be constructed and operated by the students and research staffs. It will provide training experience of enormous scale. It is based on high temperature profile control operating at principle with three RF induction heated zones and precise temperature profile control operating at temperature in excess of 2000{SYMBOL 176 \f "Symbol"}C. The system is fully automatic using adaptive PID feed-back control with a computer to monitor the entire growth cycle from heating up to growth and to cool down in all zones simultaneously. The system in its proto-form already has the capability of producing up to 125x300x10mm3 single crystal slabs. The Nd:YAG crystals produced in this new system will not contain core nor angular growth striations which are common in conventional crystal boules. The crystals produced by this process is capable to deliver multi-kilo watt power with multi-kilo hertz repetition rate and joules energy per pulse in near defraction limited beam quality so that it is deliverable via optical fibers. Our pr ocess represents a giant step forward in the Nd:YAG crystal growth technology. The proposed system will be the only one in the U.S. At present, both Japan and China have pursued the same aim with good progress. The benefit of this technology is to produce the needed Nd:YAG crystal slabs which will create a totally new generation laser manufacturing systems for a variety of industrial applications. Our growth system, once perfects its operation, can be further scaled up to produce even larger size slabs for large aperture laser beam delivery systems. It will open a total new era for both research and manufacture. Another example of potential use of this high power Nd:YAG slab laser is to build a table top soft x-ray generating system for sub-micron lithography applications. This will provide a low cost system for small to medium companies (who can not afford synchrotron radiation facilities) to be able to manufacture their own chips at any locations of their choice to compete in the market. ***

9413860 Chai 当前美国钣金（尤其是汽车）行业需要高功率和高重复率激光器，这些激光器可通过光纤传输并连接到机械臂以进行高速和高精度钻孔、切割和焊接工艺。 虽然电源和光学传输系统现已可用，但激光系统的核心——激光介质仍然缺失。 激光介质是一个大型单晶 Nd:YAG 板，它在相干（激光二极管）或非相干（闪光灯）泵浦下产生激光功率。 由于熔拉单晶中固有的核心缺陷，当前最先进的生长工艺仅限于最大 25x200x10mm3 板坯。 基于板条配置的激光器可以通过更简单的设计和更高的效率产生更多的功率。 它非常适合当前的二极管阵列泵浦设计。 我们建议构建一种新型晶体生长系统来生长此类 Nd:YAG 板。 该系统由学生和研究人员设计、构建和操作。 它将提供大规模的培训经验。 它基于高温分布控制，其原理上具有三个射频感应加热区，并且在超过 2000{SYMBOL 176 \f“符号”}C 的温度下运行精确的温度分布控制。 该系统是全自动的，使用自适应 PID 反馈控制和计算机来监控从加热到生长的整个生长周期，并同时在所有区域冷却。 该系统的原型已经能够生产尺寸高达 125x300x10mm3 的单晶板。 在这个新系统中生产的 Nd:YAG 晶体不会包含传统晶体晶锭中常见的核心或有角生长条纹。 通过该工艺生产的晶体能够以数千赫兹重复率和每脉冲焦耳能量提供数千瓦功率，且光束质量接近衍射限制，因此可以通过光纤传输。 我们的工艺代表了 Nd:YAG 晶体生长技术的巨大进步。 拟议的系统将是美国唯一的系统。目前，日本和中国都在追求同一目标，并取得了良好进展。 该技术的好处是生产所需的 Nd:YAG 晶体板，这将为各种工业应用创建全新一代激光制造系统。 我们的生长系统一旦完善其操作，就可以进一步扩大规模，为大孔径激光束传输系统生产更大尺寸的板坯。 它将开启研究和制造的全新时代。 这种高功率 Nd:YAG 板条激光器的潜在用途的另一个例子是构建用于亚微米光刻应用的桌面软 X 射线发生系统。 这将为中小型公司（买不起同步加速器辐射设施）提供一个低成本系统，使其能够在他们选择的任何地点制造自己的芯片以参与市场竞争。 ***