δ/a

ω [1015 rad/s]

  

a:

 [m]

b:

 [m]

c1:

 [m/s]

c2:

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ωmax:

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Fig. 3. For frequencies in the band gap where there are no propagating solutions, light penetrates a distance δ into a layered material. There are no waves that propagate through a layered material for frequencies where |α| >2 in the regions with the gray background. Source file.