Tilt-to-length coupling noise suppression method for the manufacturing of space gravitational wave telescopes

Abstract

Tilt-to-length (TTL) coupling noise is an essential index for evaluating the performance of space gravitational wave telescope optical systems. Manufacturing errors can cause wavefront error, low-order aberration ratio, and TTL coupling noise cancellation ratio to deviate from the ideal design value, degrading the performance of telescopes. This study proposes a method for suppressing TTL coupling noise in space gravitational wave telescope manufacturing. We first analyzed the influencing mechanism of manufacturing error on TTL coupling noise and established a mathematical model for the relationship. The relationship between manufacturing error and TLL coupling noise within the entire range of jitter angle was analyzed, and a maximum value model for TTL coupling noise in manufacturing was established. A maximum value model was used to establish an evaluation function for suppressing TTL coupling noise in telescope manufacturing. Taking the typical structure of a space gravitational wave detection telescope system as an example for design optimization. The results indicate that the probability of TTL coupling noise coefficient being less than ±25 p.m./μrad is 99 % and 50 %, respectively, when optimizing the telescope using and without the method proposed in this paper.