The Goos-Hänchen effect for surface plasmon polaritons

Area of Science:

• Condensed Matter Physics
• Plasmonics
• Optics

Background:

• Surface plasmon polaritons (SPPs) are electromagnetic waves confined to the interface between a metal and a dielectric.
• The interaction of SPPs with interfaces can lead to unique optical phenomena.
• Understanding SPP reflection is crucial for developing novel optical devices and sensors.

Purpose of the Study:

• To investigate the reflection of a surface plasmon polariton beam at a planar interface between two metals with different dielectric functions.
• To analyze the lateral displacement of the reflected SPP beam as a function of incidence angle.
• To explore the potential of this effect for sensing applications.

Main Methods:

• Utilized an impedance boundary condition.
• Employed numerical solutions of integral equations for scattering amplitudes.
• Studied the reflection of SPP beams at varying angles of incidence.

Main Results:

• Observed a significant lateral displacement of the reflected SPP beam when the incidence surface is optically denser (|ɛ2(ω)|≫|ɛ1(ω)|).
• The displacement magnitude was found to be several times the wavelength of the incident beam.
• This displacement is identified as the surface plasmon polariton analogue of the Goos-Hänchen effect.

Conclusions:

• The observed lateral displacement effect is sensitive to the dielectric properties of the metal surfaces.
• This sensitivity can be leveraged for sensing modifications in the dielectric environment of metal surfaces.
• Potential applications include detecting atomic or molecular layer adsorption on metal surfaces.