title: Methodological demonstration of laser beam pointing control for space gravitational wave detection missions.
abstract: In space laser interferometer gravitational wave (G.W.) detection missions, the stability of the laser beam pointing direction has to be kept at 10 nrad/√Hz. Otherwise, the beam pointing jitter noise will dominate the noise budget and make the detection of G.W. impossible. Disturbed by the residue non-conservative forces, the fluctuation of the laser beam pointing direction could be a few μrad/√Hz at frequencies from 0.1 mHz to 10 Hz. Therefore, the laser beam pointing control system is an essential requirement for those space G.W. detection missions. An on-ground test of such beam pointing control system is performed, where the Differential Wave-front Sensing technique is used to sense the beams pointing jitter. An active controlled steering mirror is employed to adjust the beam pointing direction to compensate the jitter. The experimental result shows that the pointing control system can be used for very large dynamic range up to 5 μrad. At the interested frequencies of space G.W. detection missions, between 1 mHz and 1 Hz, beam pointing stability of 6 nrad/√Hz is achieved.
authors.affiliation: National Microgravity Laboratory (NML), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Dong
authors.affiliation: National Microgravity Laboratory (NML), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: He-Shan
authors.initials: HS
authors.lastname: Liu
authors.affiliation: National Microgravity Laboratory (NML), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Zi-Ren
authors.initials: ZR
authors.lastname: Luo
authors.affiliation: National Microgravity Laboratory (NML), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Yu-Qiong
authors.initials: YQ
authors.lastname: Li
authors.affiliation: National Microgravity Laboratory (NML), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Jin