A Cryogenic High-Finesse Optical Cavity to Improve the Stability of Yb Optical Lattice Clocks

We report on the implementation of a high-finesse sapphire optical cavity operating in a closed-cycle cryostat at 4 K. Operation at cryogenic temperature allows suppression of thermal noise and potential for laser frequency stabilization at the low 10 −17 fractional frequency stability level. However, it complicates controlling technical sources of noise. Solutions for minimizing the impact of acceleration noise, temperature fluctuations, and residual amplitude modulation will be presented, as well as laser frequency stability characterization and preliminary results in applying the improved clock laser to the interrogation of the NIST Yb optical lattice clocks.