Recent development of a laser interferometer for Taiji space gravitational wave detection

Abstract

In this study, we developed and constructed the first-generation ultrastable optical bench (OB) for the Taiji program. The OB uses optical bonding technology, and for the first time, noise testing and calibration were performed. A comprehensive analysis was carried out on the various noise sources impacting the interferometer system; these sources included laser frequency noise, laser power noise, thermal drift noise, and angular jitter noise. When the environmental conditions fell short of our stringent requirements, an advanced post-data processing technique was employed to effectively reduce both the thermal drift noise and angular coupling noise. The results revealed that the noise level of the interferometer system reached 1.1 pm/Hz^1/2 at 1 Hz, 5 pm/Hz^1/2 at 0.1 Hz, and 8 pm/Hz^1/2 at 0.01 Hz; these levels met the requirements of the Taiji pathfinder mission. Furthermore, a future research proposal was provided, with the aim to meet the full frequency range requirements of the Taiji program.