Extremely High Q-factor metamaterials due to Anapole Excitation
  We demonstrate that ideal anapole metamaterials have infinite Q-factor. We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit anapole behavior in the sense that the electric dipole radiation is almost cancelled by the toroidal dipole one, producing thus an extremely high Q-factor at the resonance frequency. The size of the system, at the mm range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q-factor. In spite of the very low radiation losses the local fields at the metamolecules are extremely high, of the order of higher than the external incoming field. 
Alexey A. Basharin, Vitaly Chuguevsky, Nikita Volsky, Maria Kafesaki,   Eleftherios N. Economou
physics.class-ph physics.optics