Fast wavefront sensing method based on diffraction basis vectors for tightly focused optical systems.

Recently, phase retrieval techniques have garnered significant attention with their exceptional flexibility. However, their application is limited in optical systems with high numerical aperture due to the disregarded polarization properties of the beam. In this paper, a fast wavefront sensing method for tightly focused systems is proposed. Firstly, a vector diffraction model based on the chirp-Z transform is established to analytically describe the focal spot using the modal coefficients of polynomials and diffraction basis vectors, which accommodating any pixel size and resolution, thereby enabling to break through sampling constraints and remove lateral errors. Additionally, a modified Newton-gradient second-order algorithm is introduced to simultaneously optimize wavefront in multiple polarization directions, without the need for diffraction operators during iterations. Both numerical simulations and error analysis confirm the efficacy and precision of the proposed wavefront sensing method.