Plasmon induced transparency in three dimensional metamaterial of upright magnetic meta-molecules

We demonstrate a new electromagnetic mechanism of plasmon induced transparency (PIT) in three dimensional plasmonic meta-molecules at optical frequency region. Using double electron beam exposure lithography, three erected U-shape gold nano rings are integrated in a unit cell with 600 nm periodicity both in x and y directions on a fused silica substrate. By breaking geometrical symmetry, the bright element couple to the dark elements via magnetic response resulting in a stronger and broader transparency window.