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

该小型企业创新研究（SBIR）第一阶段项目将通过激光加热基座生长（LHPG）方法的修改版本，证明生长用于可见光产生的周期性极化掺镁铌酸锂高质量光纤的可行性。用于生长这些晶体的其他方法已被证明是非常昂贵的，并且导致具有非常长的周期时间的不可靠的结果，使得非线性晶体的使用对于许多应用不可行。用常规LHPG方法极化的周期性极化晶体表现出弯曲的铁电畴，这导致非线性光学转换效率的损失，使得该技术对于需要最大亮度的微型显示器应用不实用。该公司将商业化LHPG生长的周期性极化掺镁铌酸锂倍频晶体，其质量更高，价格更低，交货更快，寿命更长，比目前可用的直拉晶体。为了实现这一点，技术方法将是创建和设计一种新型的光学后加热器，其可以产生足够高的温度，以使LHPG能够生长高质量的较厚的纤维，具有直的铁电畴，从而以非常可靠和可再现的方式实现在532 nm处的高非线性光学转换效率。如果成功的话，所提出的LHPG方法将产生具有低缺陷密度和低内部应变的许多化合物的单晶纤维。它的主要局限性是无法生长直径大于0.8至1.2毫米的光纤，并且周期性极化晶体也具有直畴，从而限制了器件的光学效率。该团队将展示一种新的技术，用于生长具有更大直径和铁电畴的LHPG纤维，没有曲率。这项工作将使LHPG能够大批量生产倍频芯片，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）和其他消费电子设备的商业化，这些设备将依赖倍频激光器。该项目将有助于晶体生长理论。它将帮助研究机构的材料科学家做出进一步的发现，因为更厚的纤维更容易研究。

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.