  We demonstrate that the trapped magnetic resonance mode can be induced in an
asymmetric double-bar structure for electromagnetic waves normally incident
onto the double-bar plane, which mode otherwise cannot be excited if the double
bars are equal in length. By adjusting the structural geometry, the trapped
magnetic resonance becomes transparent with little resonance absorption when it
happens in the dipolar resonance regime, a phenomenon so-called plasmonic
analogue of electromagnetically induced transparency. Accordingly, the
additional magnetic resonance by introducing asymmetry is explained as a result
of nonlinear plasmon coupling.
