Multilayer Thin Film Interference

Photonic Crystals

S/D - This is a unit we invented to help convey the scale of the small structures we are describing.  The S stands for the structure that is being discussed and the D stands for one thickness of a U.S. dollar bill.  This unit indicates the number of structures it would take, if stacked on top of one another, to equal the thickness of a dollar bill.

The dollar is .11 mm [1 S/D] thick.