Optimized design of a gravitational wave telescope system based on pupil aberration.

The telescope is vital for accurate gravitational wave detection in the TianQin project. It must meet criteria like a geometric tilt-to-length (TTL) coupling noise ≤0.02√2 /µ and wavefront ≤/30. Analyzing the pupil aberration's impact on geometric TTL noise, we devised an optimization method using the chief ray spot diagram's standard deviation. Implementing this in Zemax with a ZPL macro, we designed an optical system meeting TianQin's requirements. The system has a maximum geometric TTL noise coefficient of 0.0250 nm/µrad over the science FOV and a wavefront RMS of 0.0111, confirming the method's feasibility.