Cryogenic Sapphire Optical Reference Cavity with 1 x 10^-16 fractional instability

Published

October 2, 2024

Author(s)

Jose Valencia, George Iskandr, Nicholas Nardelli, David Leibrandt, David Hume

Abstract

The frequency stability of a laser locked to an optical reference cavity is fundamentally limited by thermal noise in the cavity length, caused by local thermal fluctuations of the strain and index of refraction of the cavity components. These fluctuations are linked to material dissipation, which depends both on the temperature of the optical components and the material properties. Here, the design and experimental characterization of a low-thermal-noise, 10 K cryogenic, sapphire, 1069 nm optical cavity is presented. Theoretical estimates of the thermo-mechanical noise floor for this cavity indicate that a fractional frequency stability as low as $2\times10^-18}$ can be achieved. Major technical noise contributions including vibrations, temperature fluctuations, and residual amplitude modulation are characterized in detail. The fractional frequency instability is measured in two ways. The short-term performance is measured via three-cornered hat with multiple cavity-stabilized lasers, yielding a noise floor of $1\times10^-16}$. The long-term performance is measured against an optical lattice clock indicated stability at the level of $2\times10^-15}$ at averaging times up to 10,000 s.

Citation

Review of Scientific Instruments

Issue

95

Pub Type

Journals

Download Paper

https://doi.org/10.1063/5.0214790

Local Download

Keywords

Optical clock, frequency stabilization, reference cavity

Citation

Valencia, J. , Iskandr, G. , Nardelli, N. , Leibrandt, D. and Hume, D. (2024), Cryogenic Sapphire Optical Reference Cavity with 1 x 10^-16 fractional instability, Review of Scientific Instruments, [online], https://doi.org/10.1063/5.0214790, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957464 (Accessed October 10, 2025)