Spoke wheel filtering strategy for on-axis flattop shaping.
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.
Liu
Tao
T
Institute of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China.
Tan
Jiubin
J
Liu
Jian
J