Light emission via surface plasmon modes in metal semi-shell cavity shaped antennas and film coupled structure

The dipole emission into surface plasmon in a semi-shell cavity shaped metal antenna and metal film coupled structure is investigated numerically. The decay rate of the dipole emitter is found to be greatly enhanced at certain wavelength of surface plasmon resonance mode. Noradiative decay shows a near-field (∼10 nm) effect, and radiative decay dependence on the emitter-antenna distance is determined by the dipole emitter location. In particular, light emission in metal antenna-metal film coupled structures have shown a further accelerated radiative decay and a directional far-field radiation pattern due to the surface plasmon mode coupling in complex structures.