title: Spoke wheel filtering strategy for on-axis flattop shaping.
abstract: Spoke wheel filtering strategy is developed using the proposed spoke wheel filter (SWF) and solving the nonlinear optimization model established by introducing a super-Gaussian function. Theoretical calculations through simulated annealing algorithm indicate that high focal depth is obtained by increasing the number of curved sectors composing SWF, while the peak-valley intensity oscillation is reduced by bending them appropriately and slightly changing their amplitude transmittances. The transverse in-focus spot compresses when the center-shaded circle of SWF enlarging. Comparison shows that SWF outperforms radial-symmetric pupil filters in its largely reduced intensity oscillation and very flexible design of focal depth extension.
authors.affiliation: Institute of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Jiubin
authors.initials: J
authors.lastname: Tan
authors.forename: Jian
authors.initials: J
authors.lastname: Liu