LISA optical metrology: tilt-to-pathlength coupling effects on the picometer scale

Airbus Defence and Space GmbH currently investigates a number of promising payload concepts for interferometric space-bourne gravitational wave observatories; focusing on beam pointing for the laser links.1 To this end, one of the setups implements “In-Field Pointing (IFP)”, which is a payload design employing the actuation of a tiltable mirror positioned in an intermediate pupil plane of a wide field off-axis telescope. Here, the lateral alignment of actuated mirror and relay stages imaging the intermediate pupil to the detector plane using tilt-to-length coupling effects will be discussed.