GOALI: OP: Incongruent Growth of Single Crystal 3D Architecture for New Optical Functionalities in Glass

非技术描述：光子集成电路(PIC)，微电子电路的光学模拟，是通信、传感、信息、显示和其他技术的下一个重大进步的关键。与分立系统相比，它们提供了几个优势，包括更小的尺寸、更低的功耗、通过简化组件耦合和封装过程而获得更好的性能和可靠性，以及通过批量制造来降低成本。当前用于制造PIC的方法适用于平面几何结构，而实现高密度的器件元件需要制造3D系统，这对于光计算、光通信和新形式的高密度光存储器特别重要。实现这一目标的一个主要障碍是制造和集成透明的多功能微型光学元件的困难，这些元件必须是低对称性的晶体，而不是固有无源的玻璃。由利哈伊大学的研究人员领导的一个多国团队最近展示了使用飞秒(Fs)激光制造玻璃3D单晶结构(SCAG)的原理证明。为了具体实现康宁公司最近提出的“主态传输”概念，本研究进一步扩展了这一方法。它承诺将光纤的传输带宽增加一个数量级，从而促进光通信的下一次突破。与此同时，该项目正在通过与康宁公司的合作，在应用驱动研究方面培训两名研究生，吸引几名本科生，并向K-12学生介绍新兴的激光制造新结构和设备领域。技术细节：通过非线性吸收飞秒激光辐射，可以在透射光的焦点处对玻璃进行深层加热。这一特点和光束的受控平移已经被用来在一致结晶的硼锗酸镧模型组合物中制备铁电SCAG的一种可行的方法。然而，对于实际感兴趣的成分来说，玻璃到晶体的转变变得越来越复杂，因为这两个相的组成不同。因此，利哈伊大学和康宁公司的这项合作致力于对飞秒激光诱导晶体生长过程的基本了解，并将这些知识应用于制造适用于原型器件的形状和尺寸的SCAG。通过团队之间的持续反馈和相互作用，正在建立制造工艺参数、SCAG的结构和光学性能之间的相关性。这些结果正在帮助开发一种预测模型，该模型将为在复杂组合物中制造适合于设备使用的较低光学损耗的SCAG提供指导。

NON-TECHNICAL DESCRIPTION: Photonic integrated circuits (PICs), the optical analog of microelectronic circuits, are key to the next major advancement in communication, sensing, information, display, and other technologies. They offer several advantages compared to discrete systems including smaller size, lower power consumption, better performance and reliability through simplification of component coupling and packaging processes, and lower cost through batch fabrication. The methods currently employed for fabricating PICs are suitable for planar geometries, whereas achieving a high density of device elements requires fabrication of 3D systems that are particularly important for optical computing, optical communication and new forms of high density optical memory. A major hurdle toward this goal is the difficulty of fabrication and integration of transparent, multifunctional micro-optical elements, which must be crystals of low symmetry rather than glass that is inherently passive. A multinational team led by researchers at Lehigh University recently demonstrated the proof-of-principle for fabricating 3D single crystal architecture in glass (SCAG) using a femtosecond (fs) laser. The present research is extending this method further for specifically realizing the concept of "principal state transmission" recently introduced by Corning, Inc. It promises to increase the transmission bandwidth of an optical fiber by an order of magnitude, thereby facilitating the next breakthrough in optical communication. In parallel, the project is training two graduate students in application-driven research through collaboration with Corning, Inc., engaging a few undergraduate students and introducing K-12 students to the emerging field of laser fabrication of new structures and devices. TECHNICAL DETAILS: Nonlinear absorption of fs laser radiation allows heating a glass deep inside, at the focal point of the otherwise transmitting beam. This feature and controlled translation of the beam have been exploited in a viable method for fabricating ferroelectric SCAG in a congruently crystallizing lanthanum borogermanate model composition. However, the glass to crystal transformation becomes increasingly complex for compositions of practical interest, where the two phases have different compositions. Therefore, this GOALI collaboration between Lehigh University and Corning, Inc. is focusing on the fundamental understanding of fs laser-induced crystal growth process in continuously evolving composition, and applying this knowledge to fabricate SCAG of shape and size suitable for prototypic devices. Through continuous feedback and interactions between the teams, a correlation is being developed between the fabrication process parameters, structure of SCAG and optical performance. These results are helping to develop a predictive model that will provide guidelines for making lower optical loss SCAGs in complex compositions suitable for use in devices.