Resonant coupling from a new angle : coherent control through geometry

We demonstrate that interference of absorption pathways can be used to control resonant coupling of light to guided modes in a manner analogous to quantum coherent control or electronically induced transparency. We illustrate the control of resonant coupling that interference affords using a plasmonic test system where tuning the phase of a grating is sufficient to vary the transfer of energy into the surface plasmon polariton by a factor of over 10⁶. We show that such a structure could function as a one-way coupler, and present a simple explanation for the underlying physics.