| 摘要 |
The current limits of resolution of multi-element optical systems are exceeded by reducing the number of elements while introducing at the critical aperture a blazed transmission grating having grating rings of low bending power defined by multiple plateaus. By illuminating the optical train with monochromatic light that constitutes a multiplicity of distributed sources having a substantial temporal coherence but spatial incoherence and by varying the slopes and widths of the grating rings, local phase delays are introduced that adjust aberrations in the optical system, providing an aligned composite wavefront. The system and method may be used for presenting an image, as for a wafer stepper, or for viewing an image, as in a microscope.
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