Thermal Correction of Astigmatism in the Gravitational Wave Observatory GEO 600

The output port of GEO 600 is dominated by unwanted high order modes (HOMs). The current thermal actuation system, a ring heater behind one of the folding mirrors, causes a significant amount of astigmatism, which produces HOMs. We have built and installed an astigmatism correction system, based on...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2013-11
Main Authors: Wittel, Holger, Lück, Harald, Affeldt, Christoph, Dooley, Katherine L, Grote, Hartmut, Leong, Jonathan R, Prijatelj, Mirko, Schreiber, Emil, Slutsky, Jacob, Strain, Kenneth A, Was, Michal, Willke, Benno, Danzmann, Karsten
Format: Article
Language:English
Subjects:
Actuation
Astigmatism
Folding
Gravitational waves
Radius of curvature
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The output port of GEO 600 is dominated by unwanted high order modes (HOMs). The current thermal actuation system, a ring heater behind one of the folding mirrors, causes a significant amount of astigmatism, which produces HOMs. We have built and installed an astigmatism correction system, based on heating this folding mirror at the sides (laterally). With these side heaters and the ring heater behind the mirror, it is possible to tune its radius of curvature in the horizontal and the vertical degree of freedom. We use this system to match the mirrors in the two arms of GEO 600 to each other, thereby reducing the contrast defect. The use of the side heaters reduces the power of the HOMs at the output of GEO 600 by approximately 37%.
ISSN:2331-8422
DOI:10.48550/arxiv.1311.5367