摘要
In the Taiji mission, the tilt-to-length (TTL) coupling noise caused by satellite jitter is the second largest noise source that affects the accuracy of the laser interferometer. In order to ensure measurement accuracy, it is necessary to suppress this noise to ≤ ±25 μm/rad@±300 μrad. Based on Fermat's principle, an imaging system composed of biconvex lenses was designed, and the effect of the imaging system on suppressing TTL coupling noise was simulated and analyzed. A physical experiment platform was built to verify the effectiveness of the imaging system in suppressing TTL coupling noise. The simulation results showed that the TTL coupling noise was ≤ ±10 μm/rad@±300 μrad after the biconvex lens imaging system was added; the experimental results showed that the TTL coupling noise was ≤ ±15 μm/rad@±300 μrad after the biconvex lens imaging system was added. These results satisfied the requirements of the Taiji mission in terms of the level of TTL coupling noise. Moreover, the entire interference optical path was easy to control, and high measurement accuracy was achieved. The suppression effect of TTL coupling noise was verified by buliding a physical experiment platform, which laid the foundation for physics experiments of the Taiji mission laser interferometer.
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