Nonlinear surface magneto-plasmonics in Kretschmann multilayers

TL;DR

This paper explores how hybrid gold-cobalt-silver multilayer structures can enhance nonlinear magneto-plasmonic effects, especially second harmonic generation, through surface plasmon polaritons, advancing nanoscale control of nonlinear light processes.

Contribution

It demonstrates the dominant role of surface plasmon polaritons at the second harmonic frequency in magnetic second harmonic generation within multilayer structures.

Findings

Magneto-optical modulation of SHG is significant and tunable.

Surface plasmon polaritons strongly influence nonlinear optical responses.

Hybrid multilayers support propagating surface plasmon polaritons at fundamental and SH frequencies.

Abstract

The nonlinear magneto-plasmonics aims to utilize plasmonic excitations to control the mechanisms and taylor the efficiencies of the non-linear light frequency conversion at the nanoscale. We investigate the mechanisms of magnetic second harmonic generation in hybrid gold-cobalt-silver multilayer structures, which support propagating surface plasmon polaritons at both fundamental and second harmonic frequencies. Using magneto-optical spectroscopy in Kretschmann geometry, we show that the huge magneto-optical modulation of the second harmonic intensity is dominated by the excitation of surface plasmon polaritons at the second harmonic frequency, as shown by tuning the optical wavelength over the spectral region of strong plasmonic dispersion. Our proof-of-principle experiment highlights bright prospects of nonlinear magneto-plasmonics and contributes to the general understanding of the nonlinear optics of magnetic surfaces and interfaces.