Stray light measurement for space optical systems using the time-domain method.

The presence of stray light degrades the signal-to-noise ratio (SNR) of space optical payloads and, in severe cases, may lead to the loss of target data, ultimately resulting in mission failure. Stray light measurement aims to directly evaluate the impact of stray light on space optical systems and serves as a core method for determining and verifying the actual stray light suppression capability of the system. Traditional measurement methods struggle to distinguish target signals from background noise, limiting the accuracy of point source transmittance (PST) measurements. This paper proposes a time-domain stray light measurement method based on a pulsed light source and a time detector. By analyzing the characteristics of background noise and target light, filtering the temporal properties of optical signals, and achieving precise control, the method enables accurate identification of target stray light signals. Experimental results show that at an off-axis angle of 60°, the PST reached 9.32 × 10, while the background noise caused by air scattering was 3.10 × 10. This method provides a cost-effective and easily implementable solution for stray light measurement in space optical systems. It is suitable for low-threshold stray light measurement and evaluation in systems such as space gravitational wave detection and space optical telescopes.