Effect of microscopic disorder on magnetic properties of metamaterials
  We analyze the effect of microscopic disorder on the macroscopic properties of composite metamaterials and study how weak statistically independent fluctuations of the parameters of structure elements can modify their collective magnetic response and left-handed properties. We demonstrate that even a weak microscopic disorder may lead to a substantial modification of the metamaterial magnetic properties, and 10% deviation in the parameters of the microscopic resonant elements may lead to a substantial suppression of wave propagation in a wide frequency range. A noticeable suppression occurs also if more than 10% of resonant magnetic elements possess strongly different properties, but in this latter case the defects can create an additional weak resonant line. These results are of the key importance for characterizing and optimizing the novel composite metamaterials with left-handed properties at terahertz and optical frequencies. 
Maxim Gorkunov, Sergey A. Gredeskul, Ilya V. Shadrivov, and Yuri S.   Kivshar