Design and Construction of the Optical Bench Interferometer for the Taiji Program.

Area of Science:

• Astrophysics and Cosmology
• Optical Engineering
• Gravitational Wave Detection

Background:

• Space-based gravitational wave detection requires highly sensitive interferometers.
• The Taiji Program aims to detect gravitational waves in space, necessitating specialized instrumentation.
• Existing interferometers may not meet the specific demands for space missions.

Purpose of the Study:

• To design and construct a full-function two-sided optical bench interferometer (OBI).
• To meet the practical requirements of the Taiji Program for space gravitational wave detection.
• To achieve low noise levels essential for detecting gravitational waves in space.

Main Methods:

• Designed a two-sided OBI with main optical paths on the A-side and auxiliary components on the B-side.
• Utilized hydrogen-oxygen catalytic stress-free bonding technology for construction.
• Employed a self-designed precision mechanical clamping mechanism and beam position measuring device for alignment.

Main Results:

• Successfully constructed two functional OBIs.
• Controlled position and angle errors of the interference beam within 30 μm and 50 μrad.
• Stability tests in a vacuum tank on a vibration isolation platform showed OBI noise below 10 pm/√Hz (0.1 Hz to 1 Hz).

Conclusions:

• The developed OBI meets the noise budget requirements for the Taiji Pathfinder in the middle- and high-frequency bands.
• The stress-free bonding technology and precision alignment mechanisms are effective for constructing sensitive optical instruments.
• This OBI design is a significant advancement for future space-based gravitational wave observatories.