Principle and application of holographic modal wavefront sensor for extended objects and general aberration modes

By employing a computer-generated hologram (CGH) to modulate the incident wavefront, the holographic modal wavefront sensor (HMWFS) can efficiently measure multiple aberration modes in a single shot, providing significant advantages such as computational simplicity, rapid measurement speed, and customizable assessment of aberration modes. However, the current HMWFS is confined to point-like objects and aberrations with specific orthogonality, thereby limiting its application scope. In this paper, we introduce a novel HMWFS that, to the best of our knowledge, is compatible with extended objects and general aberration modes. We establish the theoretical relationship between the second moment of the image intensity and the coefficients of general aberration modes for extended objects. Simulation and experimental results confirm the feasibility and performance of the proposed HMWFS. Additionally, we demonstrated its practical use in measuring misalignments of the secondary mirror of a space telescope. Simulations show that the misalignments can be effectively corrected within 2∼3 iterations.