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Figure 8
The local diffraction intensity across a tMLL and wMLL with = 0.5 at the pupil plane. The MLL size is 62 µm, and the zone width varies from 2.5 to 5 nm. The tilting angle is 0.25° for the tMLL and 0° for the wMLL. The section depth is 10.6 µm for the tMLL (to achieve phase change in two adjacent zones) and 16.5 µm (to achieve an optimal efficiency accounting for dynamical-diffraction effect) for the wMLL. The red curve shows the corresponding phase of the pupil function of the tMLL. The simulation was performed at 20 keV. For a focal length of 10 mm, the diffraction-limited focus size is 10 nm. The inset shows the focus profile for each case.
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