Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 3: Präzisionsmessungen und Metrologie I
Q 3.2: Group Report
Monday, March 10, 2008, 14:30–15:00, 3D
A Picometer Resolution Heterodyne Interferometer for LISA and its Application to Technology Verification — •Dennis Weise1, Martin Gohlke1,2, Thilo Schuldt2,3, Thomas Heinrich3, Ulrich Johann1, Achim Peters2, and Claus Braxmaier3 — 1EADS Astrium GmbH — 2Humboldt-Universität zu Berlin — 3HTWG Konstanz
Within the LISA Mission Formulation study currently funded by ESA, EADS Astrium has developed and investigated various concepts for the LISA payload architecture, all of which utilize an Optical Readout (ORO) to detect relative motion between the inertial reference (i. e. the proof mass) and the spacecraft. In collaboration with the Humboldt University Berlin and the HTWG Konstanz, a prototype ORO has been realized over the past years, which meanwhile is close to achieving the required picometer-sensitivity in translation and nanorad-sensitivity in attitude metrology. The polarizing heterodyne interferometer is characterized by a highly symmetric setup and employs differential wavefront sensing for determination of the proof mass tilt in 2 degrees of freedom. We will discuss the experimental setup and its latest performance, as well as its application to first verification of critical LISA subsystems. For example, the interferometer has been applied to characterize the CTE of various CFRP samples with ultra-high sensitivity, including “near-zero-CTE” tubes. Our current activities further include novel developments for other critical parts of the optical metrology chain, namely the laser source and the phasemeter, where the respective approach and first results will be presented.