CAREER: Fiber-based Optical Frequency Standards Characterized With Optical Frequency Combs

智能优点：基于超快激光的稳定光学频率梳彻底改变了光学频率的测量。这些梳子在稳定到世界上最好的微波和光学标准后，已被用于许多基本常数的优雅研究。此外，它们还被用于确定容易获得的波长标准的更实际的应用。最终，每个人都可能在他或她的实验室或工厂拥有一个基于梳子的光学频率合成器。事实上，这项研究将有助于使这一梦想成为现实。对于许多应用，便携式梳子将需要低成本、便携式光学频率基准。PI建议开发基于中空、低损耗光纤的新型气室，称为光子带隙(PBG)光纤。PBG纤维电池将比它们的玻璃蒸气电池更坚固。此外，在这些单元中可以观察到更窄的吸收特征，因为光可以被限制在高强度下，而在这些纤维的核心中的损耗非常低，从而促进了对被限制在其中的分子的饱和吸收光谱。较窄的线宽将导致更高的精度。这些基于光纤的便携式标准有可能达到10-100 kHz的精度。通过将梳子稳定到这些参考，我们可能会创造出比石英振荡器更稳定的无线电频率。广泛的影响：电信行业目前依赖具有约1 GHz宽的吸收特性的气室来校准波长测量设备。这里提出的PBG光纤单元的坚固特性将增加可以包括这些分子参考的设备的范围。此外，这些标准的更高精度将满足日益密集的波长信道封装带来的日益增长的需求。稳定在这些基准上的梳子可以结合到激光雷达中，或者作为稳定的便携式射频源。这对教育的影响也将是巨大的。这项研究将雇用两名研究生和一名本科生。PI将把这项研究的各个方面纳入入门、高级本科生和研究生水平的教学中。PI已经参与了堪萨斯州立大学针对高中和六年级女孩的外展项目，并正在努力招募有才华的少数族裔大学新生加入实验室。

Intellectual Merit:Stable optical frequency combs based on ultrafast lasers have revolutionized measurements of optical frequencies. These combs, when stabilized to the world's best microwave and optical standards, have been used for many elegant investigations of fundamental constants. In addition, they have been employed for the more practical applications of determining readily accessible wavelength standards. Ultimately, everyone may have a comb-based optical frequency synthesizer in his or her laboratory or factory. Indeed, this research will contribute to making that dream a reality. Portable combs will require low-cost, portable optical frequency references for many applications. Such references are also needed to calibrate other optical frequency measurement devices currently employed in industry.The PI proposes to develop novel gas cells based on a hollow, low loss optical fiber, called photonic bandgap (PBG) fiber. PBG fiber cells will be much more robust than their glass vapor cell counter-parts. In addition, narrower absorption features can be observed in these cells, because light can be confined at high intensities with very low losses in the core of these fibers, facilitating saturated absorption spectroscopy on the molecules confined within. Narrower line widths will lead to higher accuracy. These portable, fiber-based standards have the potential for accuracies of 10 - 100 kHz. By stabilizing a comb to these references, we may potentially create radio frequencies more stable than those of a quartz oscillator.Broader Impacts:The telecommunications industry currently relies on vapor cells with absorption features ~ 1 GHz wide to calibrate wavelength measuring devices. The robust nature of the PBG fiber cells proposed here will increase the range of devices into which these molecular references can be included. Furthermore, the higher accuracy of these standards will fill the increasing demands brought on by increasingly dense wavelength channel packing. Combs stabilized to these references may be incorporated in lidar, or as a stable, portable rf source. The educational impacts will also be significant. Two graduate students and an undergraduate would be employed in the research. The PI will incorporate aspects of this research in teaching at the introductory, advanced undergraduate, and graduate levels. The PI has already become involved in outreach programs at Kansas State University that target high school and 6th grade girls, and is working to recruit a talented minority college freshmen to the lab.