Optical excitation of surface plasma waves without grating structures

TL;DR

This paper demonstrates that bimetallic surface plasma waves can be directly optically excited without gratings, are less lossy, and their losses can be controlled, opening new avenues for plasmonic applications.

Contribution

It reveals that bimetallic surface plasma waves can be directly excited optically without gratings and offers methods to control their losses, advancing plasmonic technology.

Findings

Dispersion curve cuts the light line enabling direct optical coupling.

Bimetallic SPWs can be less lossy than conventional SPWs.

Losses of these waves can be systematically controlled.

Abstract

Surface plasma waves (SPWs) are usually discussed in the context of a metal in contact with a dielectric. However, they can also exist between two metals. In this work we study these bimetallic waves. We find that their dispersion curve always cuts the light line, which allows direct optical coupling without surface grating structures. We propose practical schemes to excite them and the excitation efficiency is estimated. We also show that these waves can be much less lossy than conventional SPWs and their losses can be systematically controlled, a highly desirable attribute in applications. Conducting metal oxides are apt for experimental studies.