Measurement of the Optical Path Difference Caused by Steering Mirror Using an Equal-Arm Heterodyne Interferometer
Weizhou Zhu,
Yue Guo,
Qiyi Jin,
Xue Wang,
Xingguang Qian,
Yong Xie,
Lingqiang Meng,
Jianjun Jia
Affiliations
Weizhou Zhu
Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Yue Guo
Taiji Laboratory for Gravitational Wave Universe, School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, Hangzhou 310012, China
Qiyi Jin
Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Xue Wang
Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Xingguang Qian
Taiji Laboratory for Gravitational Wave Universe, School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, Hangzhou 310012, China
Yong Xie
Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Lingqiang Meng
University of Chinese Academy of Sciences, Beijing 100049, China
Jianjun Jia
Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
In space gravitational wave detection, the inter-satellite link-building process requires a type of steering mirror to achieve point-ahead angle pointing. To verify that the background noise does not drown out the gravitational wave signal, this paper designed a laser heterodyne interferometer specifically designed to measure the optical path difference of the steering mirror. Theoretically, the impact of angle and position jitter is analyzed, which is called tilt-to-length (TTL) coupling. This interferometer is based on the design concept of equal-arm length. In a vacuum (10−3 Pa), vibration isolation (up to 1 Hz), and temperature-controlled (approximately 10 mK) experimental environment, the accuracy is increased by about four orders of magnitude through a common-mode suppression approach and can reach 390 pm/Hz when the frequency is between 1 mHz and 1 HZ. By analogy, the optical path difference caused by the steering mirror reaches 5 pm/Hz in the 1 mHz to 1 Hz frequency band. The proposed TTL noise model is subsequently verified.
