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Free keywords:
Physics, Instrumentation and Detectors, physics.ins-det, Physics, Optics, physics.optics, Physics, Space Physics, physics.space-ph
Abstract:
In this article we describe the first investigations of the complete
engineering model of the Optical Metrology System (OMS), a key subsystem of the
LISA Pathfinder science mission to space. The latter itself is a technological
precursor mission to LISA, a space-borne gravitational wave detector. At its
core, the OMS consists of four heterodyne Mach Zehnder interferometers, a
highly stable laser with external modulator and a phase-meter. It is designed
to monitor and track the longitudinal motion and attitude of two floating
test-masses in the optical reference frame with a (relative) precision in the
picometer and nanorad range, respectively. We analyze sensor signal
correlations and determine a physical sensor noise limit. The coupling
parameters between motional degrees of freedom and interferometer signals are
analytically derived and compared to measurements. We also measure adverse
cross-coupling effects originating from system imperfections and limitations
and describe algorithmic mitigation techniques to overcome some of them. Their
impact on system performance is analyzed in the context of the Pathfinder
mission.
