Characteristics of tilt-to-length coupling with aperture diffraction effects in space-based laser interferometry
Phys. Rev. Applied 25, 064016 – Published 3 June, 2026
DOI: https://doi.org/10.1103/htt7-6tf5
Abstract
Spaceborne telescopes are critical components of gravitational wave observatories. The interaction between wave front aberrations and spacecraft jitter produces significant tilt-to-length noise, which ultimately limits measurement sensitivity. Although the impact of wave front error has been extensively studied, the influence of aperture diffraction on tilt-to-length coupling remains insufficiently explored. In this paper, an efficient optical model based on Fresnel impulse response theory is developed to simulate diffraction effects in scientific interferometers. A systematic analysis is conducted on how the first 36 Zernike aberration modes and their cross-coupling affect optical path stability, leading to the derivation of a normalized sensitivity matrix that identifies critical aberration types. Through Monte Carlo simulations, the influence of wave front quality on tilt-to-length noise is further quantified under practical constraints. The results demonstrate that a targeted suppression of jitter-sensitive aberrations, particularly those with even radial orders, can substantially reduce coupling noise. These findings provide theoretical foundations and practical strategies for optimizing the wave front error budget in future space-based gravitational wave detection missions.
