Heterodyne interferometer with sub-nm sensitivity in translation measurement and sub-μrad sensitivity in tilt measurement for the LISA inertial sensor

This study develops a heterodyne interferometer utilizing differential wavefront sensing for tilt measurement. The interferometer has sub-nm sensitivity in translation measurement and sub-μrad sensitivity in tilt measurement for the LISA (laser interferometer space antenna) inertial sensor. The interferometer design is based on maximum symmetry where reference and measurement arm have the same optical pathlength, frequency and polarization.