Heterodyne interferometer with a dual-mode HeNe laser for absolute distance interferometry

摘要

Abstract: This paper proposes a heterodyne interferometer using a dual longitudinal mode HeNe 633 nm laser for absolute distance interferometry. It can measure the fractional fringe of the synthetic wavelength by an electrical phasemeter with high acccuracy. The measuring period is very short. The common optical path configuration in the interferometer eliminates the affection of air turbulence effectively. !5