  Extraordinary transmission through subwavelength metallic apertures has been
extensively studied and demonstrated. At resonance, the coupling between
surface plasmons on both surfaces of the metallic film tunnels the photon from
the one side to the other through the subwavelength aperture with small
transmission efficiency based on the metals dielectric parameters and aperture
geometrical dimensions. Here, we report a completely different form of
extraordinary transmission, where the two subwavelength complementary apertures
when coupled with an optical cavity induce about 100% extraordinary
transmission far away from the natural plasmon resonance of the constituent
metallic apertures. Such unique cavity phase driven plasmon resonance enables
tuning of the extraordinary transmission band across wide spectral range unlike
previously reported geometry driven extraordinary transmission.
