Measuring transmitted wavefronts for non-circular apertures in broad bandwidths using discrete points

Abstract Transmitted wavefronts are usually measured by a laser interferometer of the corresponding design wavelength. The Zernike coefficient can be used to describe the transmitted wavefront of a circular aperture. However, it has some limitations in optical systems with non-circular apertures. In this paper, a method, based on discrete points, for measuring transmitted wavefronts in a broad bandwidth is presented. Simulations of monochromatic, achromatic and apochromatic systems verify the method. The system with off-axis field of view is also analyzed. The Conrady dispersion formula and apochromatic characteristic formula (ACF) are used to represent the relationship between the optical path difference (OPD) at each discrete point of the transmitted wavefront and the wavelength. We also experimentally verify this method by measuring the wavefront of the optical system with a square aperture. The results demonstrate that the method can be used to measure the non-circular wavefront in a broad bandwidth.