Open AccessLong-term stable optical cavity for special relativity tests in space
Author(s) -
Josep Sanjuán,
Klaus Abich,
Martin Gohlke,
Andreas Resch,
Thilo Schuldt,
Timm Wegehaupt,
G. P. Barwood,
P. Gill,
Claus Braxmaier
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.036206
Subject(s) - physics , noise (video) , optics , allan variance , orbit (dynamics) , stability (learning theory) , computational physics , standard deviation , statistics , mathematics , artificial intelligence , machine learning , computer science , engineering , image (mathematics) , aerospace engineering
BOOST (BOOst Symmetry Test) is a proposed space mission to search for Lorentz invariance violations and aims to improve the Kennedy-Thorndike parameter constraint by two orders of magnitude. The mission consists of comparing two optical frequency references of different nature, an optical cavity and a hyperfine transition in molecular iodine, in a low Earth orbit. Naturally, the stability of the frequency references at the orbit period of 5400 s ( f =0.18 mHz) is essential for the mission success. Here we present our experimental efforts to achieve the required fractional frequency stability of 7.4×10 -14 Hz -1/2 at 0.18 mHz (in units of the square root of the power spectral density), using a high-finesse optical cavity. We have demonstrated a frequency stability of (9±3)×10 -14 Hz -1/2 at 0.18 mHz, which corresponds to an Allan deviation of 10 -14 at 5400 s. A thorough noise source breakdown is presented, which allows us to identify the critical aspects to consider for a future space-qualified optical cavity for BOOST. The major noise contributor at sub-milli-Hertz frequency was related to intensity fluctuations, followed by thermal noise and beam pointing. Other noise sources had a negligible effect on the frequency stability, including temperature fluctuations, which were strongly attenuated by a five-layer thermal shield.