Surface plasmon drag effect in a dielectrically modulated metallic thin film

Area of Science:

• Optoelectronics
• Plasmonics
• Condensed Matter Physics

Background:

• Photo-induced voltage (PIV) is a phenomenon observed in materials upon illumination.
• Surface plasmon polaritons (SPPs) are collective electron oscillations at metal-dielectric interfaces that can confine and enhance light.
• Dielectric gratings are periodic structures used to excite and manipulate SPPs.

Purpose of the Study:

• To investigate the photo-induced voltage (PIV) effect in gold (Au) films featuring dielectric gratings.
• To understand the mechanism behind enhanced voltage generation when exciting surface plasmon polaritons (SPPs).
• To elucidate the role of momentum transfer in this optoelectronic phenomenon.

Main Methods:

• Experimental investigation of PIV across an Au film with a dielectric grating.
• Numerical simulations to model the observed PIV effect.
• Analysis of electron dynamics and momentum transfer mechanisms.

Main Results:

• Strongly enhanced voltage was observed when SPPs were excited.
• Electrons in the Au film were driven in the propagation direction of the SPP.
• Numerical simulations confirmed that a scattering force, representing momentum transfer from SPP to free carriers, explains the experimental results.

Conclusions:

• The observed enhanced voltage is attributed to the surface plasmon drag effect, analogous to the photon drag effect.
• Momentum transfer from SPPs to free carriers in the Au film is the underlying mechanism.
• This study provides a novel explanation for PIV enhancement in plasmonic nanostructures.