High performance optical cavity for fundamental physics tests in space

Abstract

The performance of optical frequency references is crucial for the success of future space missions for fundamental physics tests (BOOST, LISA, STE-QUEST). For the BOOST mission, that aims to search for Lorentz invariance, two optical frequency references based on different technologies will be compared in a low earth orbit. Both frequency references require a fractional frequency stability of 7.4x10^-(14) 1/sqrt(Hz) (in units of square root of power spectral density) at f = 0.18 mHz (equal to orbit period of 5400 s) [1]. Therefore, we developed a lengthbased optical frequency reference by stabilizing a 1064 nm Laser to an optical cavity, based on the National Physical Laboratory (NPL) design [2]. The setup is developed with emphasis to space compatibility and demonstrated a fractional frequency stability of (9+/-3)x10^(-14) 1/sqrt(Hz) at 0.18 mHz, which is at the BOOST requirement level and corresponds to an Allan deviation of 1x10^(-14) at 5400 s [3]. On short timescales below 100 s the Allan deviation is 7.5x10^(-16). We will present an overview of our current work towards a space qualified optical cavity and show a detailed analysis of the different noise sources limiting the frequency stability of our system. [1] N. Gürlebeck et al. "BOOST: A satellite mission to test Lorentz invariance using high-performance optical frequency references", Phys. Rev. D 97, 124051 (2018) [2] S. Webster and P. Gill "Force-insensitive optical cavity", Opt. Lett. 36, 3572-3574 (2011) [3] Josep Sanjuan, Klaus Abich, Martin Gohlke, Andreas Resch, Thilo Schuldt, Timm Wegehaupt, Geoffrey P. Barwood, Patrick Gill, and Claus Braxmaier, "Long-term stable optical cavity for special relativity tests in space," Opt. Express 27, 36206-36220 (2019)