Gozzard D R, Howard L A, Dix-Matthews B P, Karpathakis S F E, Gravestock C T, Schediwy S W
International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia.
Australian Research Council Centre of Excellence for Engineered Quantum Systems, Department of Physics, School of Physics, Mathematics & Computing, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia.
Phys Rev Lett. 2022 Jan 14;128(2):020801. doi: 10.1103/PhysRevLett.128.020801.
A global network of optical atomic clocks will enable unprecedented measurement precision in fields including tests of fundamental physics, dark matter searches, geodesy, and navigation. Free-space laser links through the turbulent atmosphere are needed to fully exploit this global network, by enabling comparisons to airborne and spaceborne clocks. We demonstrate frequency transfer over a 2.4 km atmospheric link with turbulence comparable to that of a ground-to-space link, achieving a fractional frequency stability of 6.1×10^{-21} in 300 s of integration time. We also show that clock comparison between ground and low Earth orbit will be limited by the stability of the clocks themselves after only a few seconds of integration. This significantly advances the technologies needed to realize a global timescale network of optical atomic clocks.
一个全球光学原子钟网络将在包括基础物理测试、暗物质搜索、大地测量和导航等领域实现前所未有的测量精度。通过实现与机载和星载时钟的比对，需要通过湍流大气的自由空间激光链路来充分利用这个全球网络。我们展示了在一条2.4公里的大气链路中进行频率传递，其湍流与地对空链路相当，在300秒的积分时间内实现了6.1×10⁻²¹的分数频率稳定性。我们还表明，地面与近地轨道之间的时钟比对在仅几秒的积分后就将受到时钟本身稳定性的限制。这显著推进了实现全球光学原子钟时间尺度网络所需的技术。
