<title>Reconstruction of the wave tilt and orientation of tilt axis using OVI</title>

Abstract

In this work the application of the Optical Vortex Interferometer (OVI) to small-angle rotation measurements is presented. OVI is based on the regular net of optical vortices. In our experimental setup a regular net of optical vortices is produced by the interference of three plane waves. Distortion of one, two or three of the interference waves results in a characteristic vortex net deformation. This deformation can be measured and related to the physical quantities being investigated. In the given paper we present the ability of the OVI to measure the deflection angle of the wave vector and its orientation in a single measurement. Two different methods which allow for comparing the geometry of the vortices net were used to analyze the results of the experiment. They were compared with the method based on the standard two beam interferogram analysis. The results show that the OVI system can be successfully used to measure the deflection and orientation of the wave vector. The vortex methodology is more accurate than classical two beam interferometry in the case of the rotation angles in the range of few arcseconds.