Self-calibrating hybrid wavelength, polarization, and time-multiplexed heterodyne interferometers for Angstrom precision measurements

Propose here unique wavelength and hybrid wavelength-polarization and wavelength-polarization-time-multiplexed heterodyne optical interferometers using an internal self-referencing scheme enabling Angstrom level sensitivity optical path-length measurements. As a first step, a proof-of-concept wavelength multiplexed scanning heterodyne interferometer is built to test the surface quality of a test mirror, demonstrating ± 100 Å profile variations with a 0.9 Å accuracy. The hybrid wavelength-polarization and wavelength-polarization-time-multiplexed interferometers can be used to form spectrally coded distributed sensors.