Adjustment of the Parallelism of two Mirrors for Wide Angle Divided Mirror Michelson Wind Imaging Interferometer

Many ways have been developed to measure atmospheric winds by detecting the Doppler shifts of airglow emission lines. The Michelson Interferometer is widely used because of its simple principle. To get the Doppler shifts to calculate the wind velocity, researchers developed four-phase-step and divided mirror technology respectively. But they face challenges in many fields. So a wide angle Michelson Interferometer combining with divided mirror and phase stepping technique is used in this paper. A new algorithm is proposed in this paper to adjust the parallelism of the two mirrors for the Michelson Interferometer. Thus a high precision parallelism of the two mirrors can be obtained to get the phase shift and calculate wind velocity. The interval of the two mirrors has maximum difference less than one tenth wavelength. The experiments were performed in visible channel to prove the feasibility of this proposed algorithm. It can also be used in other fields demanding two surfaces parallel with high precision.