Ultra-high laser frequency stabilization using spectral holes in a cryogenically cooled crystal as a frequency reference

使用低温冷却晶体中的光谱孔作为频率参考实现超高激光频率稳定

• 批准号: 215187986
• 负责人: Professor Stephan Schiller, Ph.D.
• 金额: --
• 依托单位: Institut für Experimentalphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/215187986?language=en
• 关键词: Ultra; laser; frequency; stabilization; using

Laser sources with ultra-high frequency stability are of fundamental importance for precision atomic and molecular spectroscopy, time and frequency metrology, as well as fundamental physics, such as tests of Lorentz Invariance. The currently best method is servo-stabilization of the laser frequency to a mode of a ultra-low-loss optical cavity. This yielded relative instabilities of a few parts in 1016. However, even the best optical cavities are limited in principle by thermal noise and vibration sensitivity, and these are serious difficulties on the way to even higher performance. In this work, we will pursue an alternative approach for realizing ultra stable optical frequencies, based on a crystalline material doped with rare earth ions. Appealing features of a solid-state frequency reference are compactness (size ~1 cm3), ease of handling, relative immunity to environmental variations (magnetic field, temperature, acceleration), very narrow homogeneous linewidths (0.1 – 100 kHz) at temperatures below 5 K. A particular type of spectroscopy, spectral hole burning (SHB), is used to overcome the limitations imposed by inhomogeneous broadening of the optical transitions in solids (0.1 - 10 GHz). While this approach has been investigated for a long time, only very recently the applicants’ group and a group at NIST (USA) have independently shown that the optical transitions in the Europium-doped Yttrium orthosilicate crystal (Eu3+:Y2SiO5) at 580 nm do, in fact, have the potential for ultra-high frequency stabilization both on short and on long time scales. The fundamental stability limits of this approach are different from those of a reference cavity and therefore have the potential to surpass even the highest performance cavities on both short and long time scales. Therefore, we propose to fully develop this approach with the goal of demonstrating a performance better than state-of-the art optical cavities both on short times and on long time scales (goal 1×10-16 instability on time scales between 1 and 10 s, 1×10-15 for 100 -104 s). If this is achieved, the approach could become (in combination with a femtosecond frequency comb) an alternative to the widely used Hydrogen maser. The use of cryogenics is not in itself a contradiction to simplicity and reliability since modern cryogenic techniques offer compact, easy-to-use tabletop cryostats.

具有超高频率稳定性的激光源对于精密原子和分子光谱、时间和频率计量以及洛伦兹不变性测试等基础物理至关重要。目前最好的方法是激光频率的伺服稳定。这导致 1016 中的一些部件相对不稳定。然而，即使是最好的光学腔在原理上也会受到热噪声和振动敏感性的限制，这些都是严重的困难。在这项工作中，我们将寻求一种基于掺杂稀土离子的晶体材料来实现超稳定光学频率的替代方法，固态频率基准的吸引人的特征是紧凑性（尺寸〜）。 1 cm3），易于处理，相对不受环境变化（磁场、温度、加速度）影响，在温度低于 5 K 时具有非常窄的均匀线宽 (0.1 – 100 kHz)。特殊类型的光谱，光谱烧孔（SHB）用于克服固体中光学跃迁的不均匀展宽（0.1 - 10 GHz）所带来的限制，虽然这种方法已经研究了很长时间，但直到最近申请人的小组和一个研究小组才开始研究。 NIST（美国）的研究小组独立表明，掺铕原硅酸钇晶体 (Eu3+:Y2SiO5) 在 580 nm 处的光学跃迁事实上，这种方法具有在短期和长期范围内实现超高频稳定的潜力，其基本稳定性极限与参考腔的稳定性极限不同，因此有可能在短期和长期范围内超越最高性能的腔。因此，我们建议充分开发这种方法，目标是在短时间和长时间尺度上展示比最先进的光学腔更好的性能（目标是时间上的 1×10-16 不稳定性）。范围在 1 和10 秒，1×10-15 100 -104 秒）如果实现这一点，该方法可能成为（与飞秒频率梳结合）广泛使用的氢微波激射器的替代方案。由于现代低温技术提​​供了紧凑、易于使用的台式低温恒温器，因此与简单性和可靠性相矛盾。