Improved design method for suppressing optical focal spots and experimental verification

Abstract

AbstractPupil filtering is an effective method to modulate the 3D point spread function distribution of an optical system. Based on vector Debye-Wolf diffraction integral and a new fusion optimization algorithm, an improved method is described for efficiently designing the most widely-used concentric multi-belt pupil filters. The main advantage of this method is that it actively selects the minimum belt width and the total belt number for facilitating low-cost batch processing. Pupil filters for visible and near-infrared bands have been separately designed for improving the spatial resolution of optical imaging and ultrafast laser processing. The method has been experimentally demonstrated for suppressing the optical focal spot. The proposed method can be readily modified for designing more sophisticated multi-level pupil filters for practical applications in high-resolution imaging and fine laser micromachining.KEYWORDS: Pupil filtervector diffractionoptimizationlaser micromachining Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the National Key Research and Development Program of China [grant No. 2023YFE0203800], Key Research and Development Program of Shaanxi Province [grant No. 2021ZDLGY12-06], Fundamental Research Funds for the Central Universities of China [grant No. XZD012022068], Shaanxi Provincial Department of Education Scientific Research Project [grant No. 22JK0313], Shaanxi University of Technology Science Foundation [grant No. SLGRCQD2132] and National Natural Science Foundation of China [grant No. 52105481].