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Q: Fachverband Quantenoptik und Photonik
Q 11: Präzisionsmessungen und Metrologie 2
Q 11.4: Vortrag
Montag, 12. März 2012, 15:15–15:30, V7.03
Key Optical Metrology Technologies for LISA — •Martin Gohlke1,2, Thilo Schuldt3, Ulrich Johann2, Achim Peters1, Claus Braxmaier2,3, and Dennis Weise2 — 1Humboldt University, Berlin, Germany — 2Astrium GmbH, Friedrichshafen, Germany — 3University of Applied Sciences Konstanz, Germany
To support and complement the formulation of the LISA (Laser Interferometer Space Antenna) mission, we develop and validate experimentally selected key technologies for the realization of LISA’s optical metrology system. Over the last few years, we have developed a possible realization of the test mass optical readout interferometry, which reaches now a verified end-to-end noise floor of 2 pm/√Hz in translation measurement and – through the use of differential wavefront sensing – sub-nrad/√Hz in tilt measurement. Throughout the LISA measurement band from 3× 10−5 Hz and 1 Hz, this system is close to compliance with the measurement requirements defined within the LISA mission formulation, where meanwhile the limiting noise-contributors are to a large extent well understood.
This high accuracy interferometric device has been the foundation for recent new advances in various technological elements of the LISA payload. For detection of intra-spacecraft beat signals, low-noise RF quadrant photodetectors have been developed and validated, offering an RF bandwidth of 2 to 20 MHz. For µcycle accuracy phase measurement in this frequency range, an FPGA-based phasemeter on the basis of a digital PLL is under test. We will give an overview on the current performance and latest results of all of these developments.