Reducing tilt-to-length coupling for the LISA test mass interferometer
Abstract
Objects sensed by laser interferometers are usually not stable in position or orientation. This angular instability can lead to a coupling of angular tilt to apparent longitudinal displacement—tilt-to-length coupling (TTL). In LISA this is a potential noise source for both the test mass interferometer and the long-arm interferometer. We have experimentally investigated TTL coupling in a setup representative for the LISA test mass interferometer and used this system to characterise two different imaging systems (a two-lens design and a four-lens design) both designed to minimise TTL coupling. We show that both imaging systems meet the LISA requirement of ±25 μm rad-1 for interfering beams with relative angles of up to ±300 μrad. Furthermore, we found a dependency of the TTL coupling on beam properties such as the waist size and location, which we characterised both theoretically and experimentally.
- Publication:
-
Classical and Quantum Gravity
- Pub Date:
- May 2018
- DOI:
- 10.1088/1361-6382/aab86c
- arXiv:
- arXiv:1711.10320
- Bibcode:
- 2018CQGra..35j5001T
- Keywords:
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- Astrophysics - Instrumentation and Methods for Astrophysics;
- Physics - Optics
- E-Print:
- This work will be submitted to CQG
