Angstrom sensitivity polarization multiplexed heterodyne acousto-optic interferometric sensor

To the best of our knowledge, for the first time is proposed and demonstrated an angstrom level optical path length (OPL) detection sensitivity polarization multiplexed heterodyne acousto-optic interferometric sensor. In particular, it is shown how polarization multiplexing can be combined with a single acousto-optic deflector (AOD) or Bragg cell in a self-aligning optical geometry to realize a super phase stability vibration and environment tolerant optical interferometric sensor. A proof-of-concept experiment measures the voltage dependent phase change due to the refractive index change of a liquid crystal sensor chip.