SBIR Phase I: Low Cost High Quality Nonlinear Optical Crystals for Laser Light Sources for Miniature Projectors

这个小型企业创新研究（SBIR）第一阶段项目将展示通过激光加热基座生长（LHPG）方法的改进版本，生长用于可见光产生的高质量周期性极化mg掺杂LiNbO3光纤的可行性。其他用于生长这些晶体的方法已被证明是非常昂贵的，并且导致不可靠的结果，周期时间很长，使得非线性晶体的使用在许多应用中不可行。使用传统LHPG方法极化的周期性极化晶体呈现出弯曲的铁电畴，这导致非线性光学转换效率的损失，使得该技术不适用于需要最大亮度的微型显示应用。该公司将商业化lhpg生长的周期性极化mg掺杂LiNbO3的倍频晶体，与目前可用的czochralski生长晶体相比，该晶体质量更高，价格更低，交货更快，寿命更长。为了实现这一目标，技术方法将是创建和设计一种新型光学后加热器，该加热器可以产生足够高的温度，使LHPG能够生长高质量的粗纤维，具有直铁电畴，从而以非常可靠和可重复的方式在532nm处实现高非线性光学转换效率。如果成功，LHPG方法将产生具有低缺陷密度和低内部应变的多种化合物的单晶纤维。它的主要限制是不能生长直径大于0.8到1.2毫米的纤维，也不能生长出周期性极化晶体的直畴，这限制了器件的光学效率。该团队将展示一种新技术，用于生长直径更大、铁电畴无曲率的LHPG纤维。这项工作将使LHPG实现倍频芯片的大批量生产，从而促进微型投影仪（特别是嵌入手机或其他手持设备的投影仪）和其他依赖倍频激光器的消费电子设备的商业化。这个项目将对晶体生长理论作出贡献。这将有助于研究机构的材料科学家做出进一步的发现，因为较厚的纤维更容易研究。“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”

This Small Business Innovation Research (SBIR) Phase I project will demonstrate the feasibility of growing high-quality fibers of periodically poled Mg-doped LiNbO3 for visible light generation, by a modified version of the laser heated pedestal growth (LHPG) method. Other methods used to grow these crystals have proven to be very expensive and to lead to unreliable results with a very long cycle time, making the use of nonlinear crystals non viable for many applications. Periodically poled crystals poled with the conventional LHPG method exhibit curved ferroelectric domains, which results in a loss of nonlinear optical conversion efficiency, making the technology unpractical for miniature display applications where maximum brightness is required. The company will commercialize LHPG-grown frequency doubling crystals of periodically poled Mg-doped LiNbO3 with higher quality, lower price, faster delivery, and longer lifetimes than the Czochralski-grown crystals available today. In order to accomplish this, the technical approach will be to create and engineer a novel optical after heater which can generate high enough temperatures to enable LHPG to grow high quality thicker fibers, with straight ferroelectric domains thus enabling high nonlinear optical conversion efficiency at 532nm in a very reliable and reproducible way.If successful the proposed LHPG method will produce single-crystal fibers of many compounds with low defect density and low internal strain. Its main limitation had been the inability to grow fibers with diameters larger than 0.8 to 1.2 millimeters and also with straight domains for periodically poled crystals, limiting the optical efficiency of the devices. The team will demonstrate a novel technique for growing LHPG fibers with bigger diameters and ferroelectric domains exhibiting no curvature. This work will enable high-volume manufacturing of frequency doubling chips by LHPG and thereby facilitate the commercialization of miniature projectors (especially the ones to be embedded in cell phones or other handheld devices) and other consumer electronics devices, which will rely on frequency-doubled lasers. The project will contribute to the theory of crystal growth. It will help materials scientists in research institutions to make further discoveries because thicker fibers are easier to study."This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."