Turning Nonlinearity from Limitation to Advantage in Femtosecond Fiber Amplifiers

智能价值非线性(即依赖强度的)位相积累通常会限制强超短光脉冲的传播。以前关于高能脉冲产生的工作几乎完全集中在非线性的有害影响上。基于光纤的设备为研究非线性效应提供了一个独特的机会：因为光是被引导的，所以非线性相位积累(将摧毁光束)的空间后果被抑制。康奈尔大学的一个研究小组将对基于光纤的超短光脉冲光源的极限进行理论和实验研究。几乎所有以前设计的用于高能脉冲的激光器和放大器都是基于避免非线性的。康奈尔大学的研究小组将寻求基于利用和利用非线性效应的新方法，而不是避免它们。这种方法的初步结果表明，应该可以产生峰值功率比以前用光纤设备报告的高两个数量级的稳定脉冲。这种脉冲传播机制以前没有被探索过。宽带影响拟议的研究的影响将扩展到非线性脉冲传播。在这个项目中发展的概念范围从非线性动力系统的基础科学到实用的激光仪器。与其他激光器相比，光纤激光器具有非常紧凑和坚固耐用的潜力，而且价格低廉。除了促进科学研究之外，飞秒持续时间光脉冲的光纤格式源在将短脉冲光学技术的范围扩展到诸如精密加工和疾病诊断和治疗等“现实世界”应用方面具有巨大的潜力。尽管有潜力，但短脉冲光纤激光器对科学和技术的影响有限，因为它们的性能落后于固态激光器。这项拟议的工作提供了一条将固态仪器的性能与光纤的实际好处和降低成本相结合的光纤设备的途径。拟议研究的成功将转化为可能具有商业可行性的短脉冲光纤激光器的设计，商业开发将使广泛的应用成为可能。最后，拟议的努力将与本科生和研究生课堂教学相结合。建议开发的仪器将是稳定和可靠的，因此非常适合在实验室演示中兼职使用。康奈尔大学的团队在吸引代表不足的少数族裔(主要是女性)到他的实验室方面有过往记录。预计这一趋势将继续并扩大，通过与康奈尔大学的中心建立联系，这些中心历来吸引了来自代表性不足群体的大量学生。

Intellectual MeritNonlinear (i.e., intensity-dependent) phase accumulation generally limits the propagation of intense ultrashort pulses of light. Prior work on high-energy pulse generation has focused almost entirely on the harmful effects of nonlinearity. Fiber-based devices offer a unique opportunity to investigate nonlinear effects: because the light is guided, the spatial consequences of nonlinear phase accumulation (which would destroy a beam) are suppressed. A group from Cornell University will perform theoretical and experimental studies of the limits of optical-fiber-based sources of ultrashort pulses of light. Virtually all previous designs of lasers and amplifiers for high-energy pulses are based on avoiding nonlinearity. The Cornell group will pursue new approaches based on harnessing and exploiting nonlinear effects, rather than avoiding them. Initial results of this approach suggest that it should be possible to generate stable pulses with peak powers two orders of magnitude higher than reported previously with fiber devices. This regime of pulse propagation has not been explored previously.Broader ImpactsThe impact of the proposed research will extend beyond nonlinear pulse propagation. The concepts developed in this project range from the fundamental science of nonlinear dynamical systems to practical laser instruments. Fiber lasers have the potential to be extremely compact and robust, and inexpensive compared to other lasers. In addition to facilitating scientific research, fiber-format sources of femtosecond-duration optical pulses have great potential for expanding the range of short-pulse optical techniques into "real-world" applications such as precision machining and diagnosis and treatment of disease. Despite their potential, short-pulse fiber lasers have had limited impact on science and technology, because their performance has lagged behind that of solid-state lasers. The proposed effort provides a route to fiber devices that should combine the performance of solid-state instruments with the practical benefits and reduced cost of fiber. Successes in the proposed research will translate into designs of short-pulse fiber lasers that are likely to be commercially viable, and the commercial development will enable a wide range of applications. Finally, the proposed effort will be coupled to undergraduate and graduate classroom teaching. The instruments proposed for development will be stable and reliable, and thus ideal for part-time use in laboratory demonstrations. The Cornell group has a track record of attracting under-represented minorities, primarily women, to his laboratory. This is expected to continue and expand, through connections to centers at Cornell that have historically attracted substantial numbers of students from under-represented groups.