Wavefront measurement based feedback control for automatic alignment of a high-NA optical system

摘要

Many applications of optical systems depend on focal spot quality, which depends on the alignment of the optical components. During alignment, it is difficult to monitor the spot quality because the spot position shifts with the alignment. This paper proposes to compensate for displacements of the focal spot and to monitor the spot quality by controlling the position of a Shack-Hartmann sensor. Low-order aberration data is used to control the position of a Shack-Hartmann sensor while higher-order aberrations are used to estimate focal spot quality. An experimental high numerical aperture setup is presented and the proposed method is applied. The experimental results successfully demonstrate the automatic alignment capabilities.