Theoretical estimates for practical performances of surface plasmon-polariton-mediated light-emitting diodes

There have been two contrary views to each other about surface plasmon-polariton mediated light-emitting diodes as to whether or not they could exhibit enhancement in the external efficiency available for a practical system, such as space-lighting and free-space optical communications. The problem of how many photons can be practically extracted from a highly-confined surface plasmon plays a central role in resolving the argument. In this paper, we theoretically study the frequency dependence of the gain in the directionality and the external efficiency of GaN light-emitting diodes. An external efficiency of 53 % with 4 times better directionality is theoretically estimated for green light-emitting diodes operating near 530 nm.