Coherent two-photon spectroscopy for narrow linewidth atomic clocks in thermal alkali vapours

这项工作的目标是逐步改变我们的方法，以获得一个具有良好的短期稳定性(一秒~10-13)和长期精度(~10-15)的低交换原子钟。该项目将利用当前最先进系统的特点；首先，我们将使用允许高Q系统的光学跃迁的双光子探测。其次，我们将使用对CSACs(芯片级原子钟)至关重要的碱性原子的光学致密热气。将进行的工作：-使用商用的脉冲778 nm激光器来询问弱禁带的5S1/2-5D5/2。-与紧凑型光学频率梳连接。优点：光学跃迁的双光子探测跨越了微波时钟和光学时钟之间的界限，是弥合目前两者之间存在的大约三个数量级的灵敏度鸿沟的独特机会。脉冲激光的使用使时钟状态询问的相干增强成为可能。此外，还允许有效使用商业上可获得的电信激光器和部件。转移到热原子消除了激光冷却的需要。

The goal of this work is to take a step change in our approach towards a low SWaP atomic clock with excellent short-term stability (~10-13 in one second) and long-term accuracy (~10-15). The project will harness features of the current state-of-the art systems; firstly we will use two-photon probing of an optical transition allowing for a high-Q system. Secondly, we will use optical-dense thermal gases of alkali atoms that are key to CSACs (chip-scale atomic clocks).Work to be undertaken:- Use of commercially-available, pulsed 778-nm lasers for interrogation of the weakly-forbidden 5S1/2 - 5D5/2 in rubidium. - Connection with compact optical frequency combs. - Interrogation components into a single, compact system.Benefits:Two-photon probing of an optical transition crosses the boundary between microwave and optical clocks, and is a unique opportunity to bridge the divide in sensitivity of approximately three-orders of magnitude that currently exists between them. The use of pulsed lasers enables coherent enhancement of the clock-state interrogation. This is in addition to allowing the efficient use of commercially available telecoms lasers and components. Moving to thermal atoms removes the needs for laser cooling.