The metrology system of the VLTI instrument GRAVITY
Magdalena Lippa, Stefan Gillessen, Nicolas Blind, Yipting Kok, Senol, Yazici, Johannes Weber, Oliver Pfuhl, Marcus Haug, Stefan Kellner, Ekkehard, Wieprecht, Frank Eisenhauer, Reinhard Genzel, Oliver Hans, Frank Haussmann,, David Huber, Tobias Kratschmann, Thomas Ott
TL;DR
The paper describes the design and implementation of a high-precision metrology system for the VLTI instrument GRAVITY, enabling nanometer-level differential optical path difference measurements for accurate interferometric observations.
Contribution
It introduces a novel three-beam laser metrology system with phase-shifting interferometry and lock-in detection for precise dOPD measurements in astronomical interferometry.
Findings
Achieves nanometer-level measurement precision.
Enables phase-referenced imaging and microarcsecond astrometry.
Provides a comprehensive overview of the metrology system design.
Abstract
The VLTI instrument GRAVITY combines the beams from four telescopes and provides phase-referenced imaging as well as precision-astrometry of order 10 microarcseconds by observing two celestial objects in dual-field mode. Their angular separation can be determined from their differential OPD (dOPD) when the internal dOPDs in the interferometer are known. Here, we present the general overview of the novel metrology system which performs these measurements. The metrology consists of a three-beam laser system and a homodyne detection scheme for three-beam interference using phase-shifting interferometry in combination with lock-in amplifiers. Via this approach the metrology system measures dOPDs on a nanometer-level.
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.