Cold-atom source of strontium for Quantum Technology

地球上和太空中的准确导航依赖于精确和准确的计时。更好的时钟将带来更快的数据传输、更好的定位和新的科学应用。英国国内生产总值中有很大一部分依赖于全球导航卫星系统(GNSS)技术，这一比例还在不断增加。与移动宽带服务相关的基于位置的服务正在推动进一步的增长。因此，确保来自国家计量研究所(NMI)全球网络的适当时间传播对于英国和其他发达国家的经济和基础设施的运作至关重要。然而，联网系统也有漏洞，需要通过在系统中分布独立振荡器来缓解这些风险，这些振荡器可以继续提供所需的服务。新一代光学钟的性能提高了100倍，并将增强全球导航卫星系统的能力。随着系统不断发展以利用这一更高的精度，必须改进“留存”技术，以确保连续性。原子微波钟已经商业化多年，是通信系统的核心，例如，对GPS同步做出贡献的是美国海军天文台维护的50多个设备的集合。时钟使用原子的内部能级来精确控制振荡器的频率。使用激光来探测原子跃迁的光钟比基于微波跃迁的设备好几个数量级，因为光学跃迁具有更高的频率，并被选为具有更高的‘品质因数’。激光冷却原子使计时发生了革命性的变化，这种戏剧性的变化正在蔓延到其他用于精确测量的量子技术，例如用作导航惯性传感器的物质波干涉仪和用于测量的重力仪。原子干涉测量在基础物理中也有重要的研究应用，例如新型的暗物质和引力波探测器。正在开发的建造大基线(千米尺度)原子干涉仪的实验方法利用了锶原子中极窄的时钟跃迁的特殊性质，并采用了为光学时钟开发的技术。该项目旨在开发一种激光冷却锶原子源，这是制造下一代此类量子设备的供应链中的关键组件。该项目将支持将高通量冷原子源锶发展到技术准备水平，以便提供给其他人用于集成到仪器中。我们还将测试原子源的新方面，如脉冲操作以延长寿命，这是在研究实验室之外部署时钟和量子仪器的一个重要考虑因素，例如在访问受到限制的深井中建造超大规模干涉仪的项目。

Accurate navigation on earth and in space relies on precise and accurate timekeeping. Better clocks will give faster data transfer, improved positioning, and new science applications. A significant and increasing fraction of the UK GDP depends on Global Navigation Satellite Systems (GNSS) technologies. Location based services associated with mobile broadband services are driving further growth. Thus ensuring the proper dissemination of time from the worldwide network of National Metrology Institutes (NMIs) is essential to the functioning of the economy and infrastructure of the UK, and other developed countries. Networked systems have vulnerabilities, however, and these risks need to be mitigated by having standalone oscillators distributed in the system that can continue providing the required service. The new generation of optical clocks provides a 100 times better performance and will enhance the capabilities of GNSS. As systems evolve to make use of this higher precision it is vital to improve the `holdover' technology in order to guarantee continuity. Atomic microwave clocks have been available commercially for many years and are at the heart of communication systems, e.g. a contributor to the synchronization of GPS is the ensemble of over 50 devices maintained at the US Naval Observatory. Clocks use the internal energy levels of atoms to control the frequency of an oscillator accurately. Optical clocks that use lasers to interrogate atomic transitions are several orders of magnitude better than devices based on microwave transitions because the optical transitions have higher frequency and are chosen to have a higher 'quality factor'. Laser cooling of atoms has revolutionised timekeeping and this dramatic change is spreading to other quantum technologies for precision measurements such as matter-wave interferometers used as inertial sensors for navigation and gravimeters for surveying. There are also major research applications of atom interferometry in fundamental physics such as new types of detector for dark matter and gravitational waves. The experimental methods that are being developed to build atom interferometers with large baselines (kilometre scale) use the special properties of the extremely narrow clock transition in strontium atoms and adapt the technology that has been developed for optical clocks. This project seeks to develop a source of laser-cooled strontium atoms that is a key component in the supply chain for the fabrication of the next generation of such quantum devices.This project will support the development of a high-flux cold-atom source of strontium to a Technology Readiness Level at which it can be supplied to others for integration into instruments. We will also test new aspects of atom sources such as pulsed operation to prolong the lifetime, which is an important consideration for the deployment of clocks and quantum instruments outside of research laboratories, for example in projects to build very large-scale interferometers in deep shafts where access is restricted.