Description and implementation studies on field dependent wavefront aberration

Zernike polynomials have been widely used to fit lens surface figure error and the wavefront aberration of optical systems, for its orthogonality in the unit circle and its corresponding relationships with optical aberrations1. Because the current extensively used Zernike polynomials are just functions of the aperture, without consideration of the field factor, it can only represent single field wavefront aberration. This is incomplete for the description of the wavefront aberration, especially for lithographic lens with a large field and high imaging quality2. Thus, considering the field factor in the description of wavefront aberration becomes very necessary. This paper presents a convenient and practical method to describe the full field wavefront aberration. A rotationally symmetric optical system has been taken as an example, in the scope of normalized full field, taking the Chebyshev zero points as nodes, and applying the Chebyshev polynomials to the fitting of Zernike coefficients of different fields. Meanwhile, the influence of the degree of Chebyshev polynomials and the number of fitting nodes on the fitting accuracy is taken into account. The results show that the fitting method used in this paper is of high accuracy, and this fitting method is very significant for the analysis of full field wavefront aberration.