OP: Spatiotemporal Dynamics of Multimode Optical Pulse Propagation: New Route to High-Performance Fiber Lasers

职务名称：基于允许许多重叠光模式的光纤的高性能激光器摘要非技术描述：产生非常短的光脉冲（持续时间为百万分之一秒）的激光器已经开始发现从组织中的细胞成像到外科手术到工业材料处理的应用范围。 这种激光器可以由光纤制成，这是有吸引力的，因为光自动保持在光纤内。在迄今为止用于此目的的光纤中，光纤的纤芯非常小（几百万分之一米），并且只有单模或图案的光在光纤中传播。这种模式是大多数人与激光束联系在一起的模式：一个在其中心最亮的小点。如果光纤的纤芯做得更大，其他图案就可以传播。所有允许的模式都是重叠的，所以出来的光束是它们的复杂混合。 当光场在光纤中传播时，光场在空间和时间上变化。基于多模式的激光理论上可以达到更高的功率，这是应用所需要的，但模式必须受到控制。对图案的控制还将允许新的能力，例如在新波长（颜色，包括红外线和紫外线）下产生短光脉冲。 在过去几年中，理论理解和实验技术的进步为研究人员提供了开发基于具有许多重叠图案或模式的光纤的激光器的工具。来自康奈尔大学和中央佛罗里达大学的研究小组将致力于开发基于这种光纤的激光器和其他短光脉冲源。 谁在这个项目工作的研究生将接受理论和实践培训，并将在科学和技术的各种职业生涯做好准备。为了增加科学的曝光率和提高参与者的多样性，康奈尔大学集团将与4H组织合作，提供旨在让初中生接触科学和可能的职业的研讨会。 技术描述：康奈尔大学的一个研究小组将对支持电磁场多种横模的光纤中超短光脉冲的传播进行理论和实验研究。由于对本质上固有地时空的多模脉冲传播的理解的最新进展，现在可以开始设计基于多模光纤的超短光脉冲源。高功率激光器和宽调谐强红外脉冲源将被建造和研究。来自中央佛罗里达大学的合作者将提供计算支持。超快科学领域已经在很大程度上建立了基于腔的单横模的短脉冲激光器，或者支持单横模的光纤。利用时空波的传播来设计新的超短脉冲源，以前没有被考虑过。新的脉冲整形机制，将被调查提供增强或全新的高能量和超短脉冲的能力。光纤为研究新的非线性波提供了理想的环境。在所提议的努力中获得的知识将与基于模分复用的未来电信系统有关。在这个项目中研究的非线性动力学将对应于各种系统中的相关效应，如玻色-爱因斯坦凝聚体，多模传播将与湍流的光学研究有关。

Title: High-Performance Lasers Based on Optical Fibers that Allow Many Overlapping Light ModesAbstractNontechnical Description:Lasers that produce very short pulses of light (millionths of millionths of seconds in duration) have begun to find applications that range from imaging of cells in tissue to surgery, to industrial material processing, as examples. Such a laser can be made of optical fiber, which is attractive because the light is automatically kept inside the fiber. In fibers used for this purpose to date, the core of the fiber is very small (a few millionths of a meter) and only a single mode, or pattern, of the light propagates in the fiber. This mode is what most people associate with a laser beam: a small spot that is brightest in its center. If the core of the fiber is made larger, other patterns can propagate. All of the allowed patterns overlap, so the beam that comes out is a complicated mix of them. The light field varies in space and in time as it propagates in the fiber. Lasers based on multiple patterns can theoretically reach much higher powers, which are needed for applications, but the patterns must be controlled. Control of the patterns will also allow new capabilities, such as the generation of short light pulses at new wavelengths (colors, including infrared and ultraviolet). Advances in theoretical understanding and experimental techniques in the last few years now give researchers the tools to develop lasers based on fibers with many overlapping patterns or modes. Groups from Cornell University and the University of Central Florida will work to develop lasers and other sources of short light pulses based on such fibers. Graduate students who work on this project will receive theoretical and practical training, and will be prepared for diverse careers in science and technology. In an effort to increase exposure of science and enhance diversity of participants, the Cornell group will work with the 4H organization to offer workshops aimed at exposing junior-high-school students to science and possible careers. Technical Description:A group from Cornell University will perform theoretical and experimental studies of the propagation of ultrashort light pulses in optical fibers that support many transverse modes of the electromagnetic field. As a result of recent advances in understanding of multimode pulse propagation, which is inherently spatiotemporal in nature, it is now feasible to begin to design sources of ultrashort light pulses based on multimode fiber. High-power lasers, and sources of broadly-tunable intense infrared pulses will be constructed and studied. Collaborators from the University of Central Florida will provide computational support.The field of ultrafast science has been built largely with short-pulse lasers based on a single transverse mode of a cavity, or optical fibers that support a single transverse mode. Exploitation of spatiotemporal wave propagation for the design of new sources of ultrashort pulses has not been considered previously. The new pulse-shaping mechanisms that will be investigated offer enhanced or completely-new capabilities for high-energy and ultrashort pulses. Optical fiber offers an ideal setting to study new nonlinear waves. Knowledge gained in the proposed effort will be pertinent to future telecommunications systems based on mode-division multiplexing. The nonlinear dynamics investigated in this project will correspond to related effects in a variety of systems, such as Bose-Einstein condensates, and multimode propagation will be relevant to optical studies of turbulence.