The off-axis parabolic mirror optical axis adjustment based on cyclic shearing interferometer

Abstract

In this paper we demonstrate a new technique in which we use the portable alignment device of an off-axis parabolic mirror optical axis adjustment, the cyclic shearing interferometer and the CCD camera to rapidly and accurately align the optical axis of an off-axis parabolic (OAP) mirror. In this method the optical axis of an OAP mirror is made parallel to the “five incident parallel laser beams” in the plane of incidence, by checking direction of these five reflected laser beams and changing the height and orientation of the OAP mirror. The cyclic interferometer is referred to as the layout where two beams travel in same directions, encountering exactly the same components until they emerge to form interference pattern. The cyclic shearing interferometer uses to examine the parallel of five incident parallel laser beams. This fast aligning method for finding the optical axis of an OAP mirror can measure the Slant Focal Length deviation to an accuracy of 0.3 %.