Long-range plasmons in an asymmetric four-layer metal–dielectric structure

The problem of existence of a long-range surface electromagnetic wave in an asymmetric structure with a thin metal film is considered. Experimental observations of the anomalous reflection of light from the surface of a corrugated structure are used to demonstrate the excitation of a long-range wave in such a structure. The possibility of using such long-range plasmons in sensor applications, when the plasmons are excited by a diffraction grating, is considered.