Picometer Sensitive Prototype of the Optical Truss Interferometer for LISA

Abstract

The optical truss interferometer (OTI) is a contingent subsystem proposed for the LISA telescopes to aid in the verification of a $1\frac{\mathrm{pm}}{\sqrt{\mathrm{Hz}}}$ optical path length stability. Each telescope would be equipped with three pairs of compact fiber-coupled units, each forming an optical cavity with a baseline proportional to the telescope length at different points around the aperture. Employing a Pound-Drever-Hall approach to maintain a modulated laser field on resonance with each cavity, the dimensional stability of the telescope can be measured and verified. We have designed and developed prototype OTI units to demonstrate the capability of measuring stable structures, such as the LISA telescope, with a $1\frac{\mathrm{pm}}{\sqrt{\mathrm{Hz}}}$ sensitivity using a set of freely mountable fiber-injected cavities. Aside from its initial motivation for the telescope, the OTI can also be readily integrated with other systems to aid in ground testing experiments. In this paper, we outline our experimental setup, measurement results, and analyses of the noise limitations.

10 pages, 10 figures

References in corpus (7)

• LISA technology and instrumentation
• Thermo-optic noise in coated mirrors for high-precision optical measurements
• Thermal noise in optical cavities revisited
• LISA long-arm interferometry
• Mathematical model of thermal shields for long-term stability optical resonators
• Suppression of residual amplitude modulation effect in the Pound-Drever-Hall locking
• Optical Truss Interferometer for the LISA Telescope