Hill Ian R, Hendricks Richard J, Donnellan Sean, Gaynor Paul, Allen Ben, Barwood Geoffrey P, Gill Patrick
Opt Express. 2021 Oct 25;29(22):36758-36768. doi: 10.1364/OE.436019.
We describe a 'clock control unit' based on a dual-axis cubic cavity (DACC) for the frequency stabilisation of lasers involved in a strontium optical lattice clock. The DACC, which ultimately targets deployment in space applications, provides a short-term stable reference for all auxiliary lasers-i.e. cooling, clear-out, and optical lattice-in a single multi-band cavity. Long-term cavity drift is compensated by a feed-forward scheme exploiting a fixed physical relation to an orthogonal second cavity axis; either by reference to an ultrastable 698 nm clock laser, or by exploiting the differential drift between orthogonal axes extracted by a single laser in common view. Via a change of mirror set in the cavity axis accessed by the clock laser, the system could also provide stabilisation for sub-Hz linewidths at the 698 nm clock wavelength, fulfilling all stabilisation requirements of the clock.
我们描述了一种基于双轴立方腔（DACC）的“时钟控制单元”，用于稳定锶光晶格钟中涉及的激光器的频率。DACC最终目标是应用于太空，它在单个多波段腔中为所有辅助激光器（即冷却、清除和光晶格激光器）提供短期稳定参考。通过利用与正交第二腔轴的固定物理关系的前馈方案来补偿长期腔漂移；要么参考超稳定的698 nm时钟激光器，要么利用由共同视野中的单个激光器提取的正交轴之间的差分漂移。通过改变时钟激光器访问的腔轴中的镜组，该系统还可以在698 nm时钟波长下为亚赫兹线宽提供稳定，满足时钟的所有稳定要求。
