Absolute laser frequency stabilization for LISA

Abstract

The LISA space mission requires laser frequency pre-stabilization of the 1064 nm laser sources. While cavity-based systems are the current baseline, laser frequencies stabilized to a hyperfine transition in molecular iodine near 532 nm are a possible alternative. Several setups with respect to space applications were developed, putting special emphasis on compactness and mechanical and thermal stability of the optical setup. Vibration testing and thermal cycling were performed. These setups show frequency noise below 20 Hz/Hz − − − √ Hz for frequencies between 4 mHz and 1 Hz with an absolute frequency reproducibility better than 1 kHz. They fulfil the LISA requirements and offer an absolute laser frequency simplifying the initial spacecraft acquisition procedure. We present the current status of iodine-based frequency references and their applicability in space missions, especially within the LISA mission.