Thermoelasticity-induced interferometer-displacement noise from the test mass in spaceborne gravitational-wave detectors
Phys. Rev. Applied 26, 024035 – Published 13 August, 2026
DOI: https://doi.org/10.1103/7jv7-zw4y
Abstract
In spaceborne gravitational-wave detectors, the test mass is treated as an ideal rigid end mirror for interferometric-displacement readout. In reality, however, as a thermoelastic body, it deforms under radiative heating from the surrounding electrode housing, shifting the effective laser-reflection point and coupling into displacement noise. In this work, we develop a coupled model of radiative heating, thermoelastic deformation, and laser sensing and derive an analytical expression relating housing temperature fluctuations to displacement noise. Applying TianQin parameters, the result shows that a displacement noise allocation of requires electrode-housing temperature fluctuations below at and at .
