Diffractive optics enables to make:
diffraction gratings
micro lenses
Fresnel lenses
With different direct or indirect etching technologies, for example with electron beams or through a mask.
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![[zoom...]](javascript:window.open(%22../res/fig_21_1.jpg%22,%22_blank%22,%22width=%22+Math.min(800,screen.availWidth)+%22,height=%22+Math.min(600,screen.availWidth)+%22,left=%22+(screen.availWidth-800)/2+%22,top=%22+(screen.availHeight-600)/2+%22,scrollbars=yes,resizable=yes%22)?void(0):void(0)){kind=link}