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zone plate

noun, Optics.
a plate or screen with alternating opaque and transparent concentric rings that focus light by diffraction.
Origin of zone plate
1895-1900 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for zone plate
  • In the future, some of these versions might add refractive power to the zone plate, achieving some level of target magnification.
  • Testing of the condenser zone plate's illumination revealed an error in its focusing ability.

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