Periodic modulation of extraordinary optical transmission through subwavelength hole arrays using surrounding Bragg mirrors

The enhanced light transmission through an array of subwavelength holes surrounded by Bragg mirrors is studied, showing that the mirrors act to confine the surface plasmons associated with the extraordinary optical transmission effect, forming a surface resonant cavity. The overall effect is increased light transmission intensity by more than a factor of 3 beyond the already enhanced transmission, independent of whether the Bragg mirrors are on the input or the output side of the incident light. The geometry of the Bragg mirror structures controls the enhancement and can even reduce the transmission by half. By varying these geometric parameters, we were able to periodically modulate the transmission of light for specific wavelengths, consistent with the propagation and interference of surface plasmon waves in a resonant cavity. Finite difference time domain simulations and a wave propagation model verify this effect.