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

这项工作的目标是朝着具有出色的短期稳定性（~10-13秒）和长期精度（~10-15）的低SWaP原子钟的方法迈出一步。该项目将利用当前最先进系统的特点；首先，我们将使用双光子探测允许高q系统的光学跃迁。其次，我们将使用碱原子的光密集热气体，这是CSACs（芯片级原子钟）的关键。将要进行的工作：-使用市售的778纳米脉冲激光器来探测铷中弱禁的5S1/2 - 5D5/2。-连接紧凑型光频梳。-审问组件成一个单一的，紧凑的系统。优点：光跃迁的双光子探测跨越了微波时钟和光学时钟之间的边界，是一个独特的机会，可以弥合它们之间目前存在的大约三个数量级的灵敏度鸿沟。脉冲激光的使用使时钟状态询问的相干增强成为可能。除此之外，还允许有效地利用商业上可用的电信激光器和组件。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.