Ultra-precise, Shock-resistant Optical Clocks (USOC)

精确的计时和同步系统对我们的生活有着显著的影响。在幕后，精确的定时支撑着我们的数字通信网络、雷达系统和全球卫星导航系统（GNSS），如GPS。几十年来，原子钟提供的异常精确的计时对我们国家和国际基础设施的这些元素至关重要。虽然传统的微波原子钟已经具有令人印象深刻的精度，低至10^14的1分之一，但自从发明了一种新的精确测量光学频率的方法（参见2005年诺贝尔物理学奖）以来，原子钟技术在过去的20年里经历了一场革命。使用新的“光学”原子钟，现在可以比以往更精确地测量时间，不确定度降至10^19的几个部分。这些光学时钟在基础科学中有着令人兴奋的应用：例如，由于广义相对论的微妙影响，当它们的高度距离地面只有1毫米的变化时，我们可以观察到它们以不同的速率滴答作响。然而，如果光学时钟可以部署在实验室之外，它们也可以对我们的生活产生重大的实际影响——例如，它们可以提高我们数字通信网络的速度和弹性。在这个项目中，我们正在开发一种新型的光学原子钟，它不仅可以比目前的实验室光学钟更精确地测量时间，而且足够坚固，可以离开实验室，部署在通信网络等现场应用中。在我们的时钟的核心，我们稳定了原子的光学“滴答声”，而不是使用更传统的脉冲稳定技术。这种持续的稳定性在短测量时间内将时钟的精度提高了100倍，并大大降低了对机械冲击的敏感性-这是开发便携式可部署时钟的不可逾越的障碍。

Precise timing and synchronisation systems have a remarkable impact on our lives. Behind the scenes, precise timing underpins our digital communication networks, radar systems, and global satellite navigation systems (GNSS) such as GPS. The exceptionally precise timing offered by atomic clocks has been essential for these elements of our national and international infrastructure for several decades.While traditional microwave atomic clocks already have impressive precision down to 1 part in 10^14, atomic clock technology has undergone a revolution in the past two decades, since the invention of a new, accurate method to measure optical frequencies (see 2005 Nobel Prize in physics). Using the new `optical' atomic clocks, it is now possible to measure time more precisely than ever, with uncertainty down to a few parts in 10^19. These optical clocks have exciting applications in fundamental science: for example, we can observe them ticking at different rates when they are changed in height by as little as 1 mm from the ground, due to subtle effects of general relativity. However, if optical clocks could be deployed outside the laboratory, they could also have a significant practical impact on our lives - for example, they could enhance the speed and resilience of our digital communication networks.In this project, we are developing a new type of optical atomic clock which can not only measure time with even greater precision than current laboratory optical clocks, but will be robust enough to leave the laboratory and be deployed in field applications such as communication networks. At the core of our clock, we stabilise the optical ``ticks'' to the atoms continuously, rather than using more traditional pulsed stabilisation techniques. This continuous stabilisation improves the precision of the clock at short measurement times by a factor of up to 100, and greatly reduces sensitivity to mechanical shocks - which is otherwise an insurmountable barrier to developing portable, deployable clocks.