SBIR Phase I: Large Aperture, Periodically Poled, Hydrothermal Potassium Titanyl Phosphate for Highly Efficient Frequency Conversion of High-Power Solid-State and Fiber Lasers

这项小企业创新研究(SBIR)第一阶段项目计划研究用于准相位匹配激光频率转换的大口径周期性铁电域光栅的可行性。这项工作的关键创新是使用低温水热法生长的磷酸钛钾(LTH-KTP)作为非线性光学衬底材料。使用LTH-KTP将实现简化的极化工艺，从而提高制造成品率，降低元件成本，并允许制造高质量的大口径(2 Mm)周期性极化晶片。水热法生长的KTP厚晶片能够定期极化，再加上其高抗光损伤性(500 mW/cm2)，将使高功率激光光源能够进行高效的波长转换，用于基于激光雷达的遥感应用，包括日益重要的国土安全领域--化学和生物制剂的对峙检测。第一阶段工作的预期结果包括使用微电极技术演示LTH-KTP中的周期性极化，以及初步评估不同极化配置对域光栅质量的影响。在第二阶段的工作中，极化技术将得到改进，并将制造出适合商业应用的光栅结构。水热法生长的KTP厚晶片具有周期性极化的能力，加上其高抗光损伤能力，将使高功率Yb光纤和二极管泵浦的固体Nd：YAG激光光源实现高效的非线性光学频率转换。激光光源具有更高的脉冲能量、波长灵活性和良好的光束质量，将在民用和军事应用中得到应用。具体应用包括基于激光的材料加工(切割、焊接和标记)、用于化学和生物制剂对峙检测的遥感、环境监测、森林管理以及基于激光雷达的导弹识别、跟踪和瞄准。

This Small Business Innovation Research (SBIR) Phase I project proposes to investigate the feasibility of fabricating large-aperture, periodic ferroelectric domain gratings for quasi-phase matched laser frequency conversion. The key innovation in this effort is the use of low temperature hydrothermally grown potassium titanyl phosphate (LTH-KTP) as the nonlinear optical substrate material. Using LTH-KTP will enable a simplified poling process, resulting in increased fabrication yields, lower component costs as well as allow the fabrication of high-quality, large aperture (2mm) periodically poled wafers. The ability to periodically pole thick wafers of hydrothermally grown KTP, combined with its high resistance to optical damage (500MW/cm2) will enable highly efficient, wavelength conversion of high-power laser sources for use in Lidar-based remote sensing applications including the increasingly important Homeland Security area of standoff detection of chemical and biological agents. The anticipated results of the Phase I effort include a demonstration of periodic poling in LTH-KTP using the micro-electrode technology and a preliminary assessment of the effect different poling configurations have on the quality of the domain grating. In the Phase II effort, the poling technology will be refined and grating structures suitable commercial applications will be fabricated.The ability to periodically pole thick wafers of hydrothermally grown KTP, combined with its high resistance to optical damage will enable highly efficient, nonlinear optical frequency conversion of high-power ytterbium fiber and diode pumped solid state Nd: YAG lasers sources. Laser sources with increased pulse energies, wavelength flexibility, and excellent beam quality, will find use in both civilian and military applications. Specific applications include laser-based material processing (cutting, welding and marking), remote sensing for standoff detection of chemical and biological agents, environmental monitoring, forest management as well as Lidar-based missile identification, tracking, and targeting.