A line of point scatterers behave approximately as a partial mirror. When the scatterers are arranged in a crystal, each line will reflect light, and all of those reflections will interfere with each other.
(Animation made for scalar fields in 2D)
<a href="//commons.wikimedia.org/wiki/User:Berto" title="User:Berto">Jacopo Bertolotti</a>
2020-05-15
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