Summary and Conclusions

Abstract

Throughout this work we have extensively explored several applications of optical cavities in the frontier of experimental physics. Part I of the thesis described the development of a novel ultra-stable optical reference cavity for use in optical atomic clocks, which is shown to be mainly limited by fundamental thermal noise at a few seconds of integration time, with a relative stability better than 1 part in $10^{16}$ at 2 s of integration. Achieving such stability required designing a long $\sim$0.5 m ULE cavity, which put very tight constraints on the vibration, temperature and pressure noise levels of the system. We have detailed the modelling and experimental techniques that are developed in order to realise this device (Chap. 2), and to keep all sources of noise below the required levels (Chaps. 3 and 4).