Comparison of Modal to Nodal Approaches for Wavefront Correction

摘要

The turbulent atmosphere aberrates optical wavefronts as they propagate through it. These aberations are reponsible for limiting the performance of large aperture ground based optical systems. The issue of whether to implement nodal or modal influence functions to perform wavefront correction in an adaptive optical system is studied. Theoretically, modal wavefront correction. is simpler to implement than nodal wavefront correction. This is true for very low mode aberrations, (e.g., tilt, focus). However, for large aperture, visible wavelength, adaptive optical imaging systems the number of modes which are required to be corrected becomes very high. Consequently, for these systems, nodal wavefront correction is more easily implemented. Keywords: Optical wavefronts; Adaptive optical system; Zernike polynomials; Nodal wavefront correction; and Modal wavefront correction.