Figuring Thin Optical Components Using Ultrashort Pulsed Laser Stress

这笔赠款将支持与制造镜片和反射镜等轻型光学部件相关的新知识的研究。激光应力弯曲是一种制造工艺，包括在导致材料永久弯曲成特定形状的条件下，将激光聚焦到玻璃镜或其他光学部件中。轻型光学元件对国防至关重要，如在太空通信和远程成像方面，以及在虚拟现实耳机或智能手机等消费设备中。激光应力弯曲有可能以比今天低得多的成本制造出精确的、轻质的光学元件，因为加工速度可以高于现有的光学制造技术。激光应力计算过程尚未完全了解，该奖项支持基础研究，以提供必要的知识，帮助推动激光应力弯曲成为有利于美国经济、社会和国防的工业过程。这项多学科的研究结合了制造、材料科学、光学和机械工程，将加强工程教育。这项研究将提供研究培训活动，以扩大包括第一代学生在内的未被充分代表的群体的参与。高纵横比光学基板的激光应力计算可以提供与传统抛光类似的材料去除率，但在镀膜或安装后应用，可能具有更高的精度。超短脉冲激光应力测量依赖于在特定位置产生可控、可重复和稳定的应力。这种激光产生的应力至少由四种机制驱动，取决于工艺参数：致密化、纳米级形成、爆炸空洞形成和淬火。这项研究填补了在这些区域内产生的应力和光脉冲之间的知识空白，解决了应力的稳定性和重复性，以及这种应力在成形光学元件中的用途。研究团队将使用空间成形超短激光脉冲和原位曲率测量进行实验，以测量多方向应力，模拟微观应力和宏观变形之间的关系，测量成型玻璃基板的强度和稳定性，并量化与制造相关的数量，如等效材料去除率、精度和收敛速度。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support research that will contribute new knowledge related to manufacturing lightweight optical components like lenses and mirrors. Laser stress bending is a manufacturing process involving focusing a laser into glass mirrors or other optical components under conditions which lead to the material permanently bending into a particular shape. Lightweight optical components are critical for national defense as in space communication and remote imaging, and consumer devices as in virtual reality headsets or smartphones. Laser stress bending has the potential to create accurate lightweight optical components at far lower cost than is possible today because the process speed can be higher than existing optical manufacturing techniques. The laser stress figuring process it not yet fully understood, and this award supports fundamental research to provide knowledge needed to help advance laser stress bending to an industrial process that can benefit the U.S. economy, society, and national defense. This multi-disciplinary research combines manufacturing, materials science, optics, and mechanical engineering and will enhance engineering education. This research will provide research training activities that broaden participation of underrepresented groups including first-generation students.Laser stress figuring of high-aspect ratio optical substrates can provide similar equivalent material removal rate as conventional polishing but applied after coating or mounting and with potentially higher accuracy. Ultrashort pulsed laser stress figuring depends on creating controllable, repeatable, and stable stress at specific locations. Such laser-generated stress has been shown to be driven by at least four mechanisms depending on process parameters: densification, nanograting formation, explosive void formation, and quenching. This research fills the knowledge gap of between the generated stress and the optical pulses within these regimes, addressing the stability and repeatability of the stress, and the utility of this stress in shaping optical components. The research team will conduct experiments using spatially shaped ultrashort laser pulses and in-situ curvature metrology to measure multi-directional stress, model the connection between microscopic stress and macroscopic deformation, measure strength and stability of shaped glass substrates, and quantify manufacturing-relevant quantities such as equivalent material removal rate, accuracy, and convergence rate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.