Study of thermal disturbances at low frequency in high precision optical metrology

Abstract

Current research aiming at test of fundamental physics, like mea-suring gravitational waves, require environments being highly stable over long times in order to achieve high precision in the low frequency band, i.e. the millihertz. Temperature noise is the main contribu-tion in these time scales and therefore it needs to be either suppressed or actively compensated. In this study we show the development of a Mach-Zehnder interferometer into an ultra-stable thermal environ-ment. The set-up is based on the deep phase modulation scheme which reduces the complexity of the hardware implementation. To achieve such a stable environment, the interferometer is located into a passive thermal shield inside a vacuum chamber. Moreover, an active control is also applied to reduce laboratory perturbations. We applied a series of thermal injections to characterize the set-up and show the agree-ment between the measured transfer function and the predicted by an analytical model.