Coupled mode enhanced giant magnetoplasmonics transverse Kerr effect

Area of Science:

• Magnetoplasmonics
• Nanophotonics
• Optical effects in magnetic materials

Background:

• The transverse magneto-optical Kerr effect (TMOKE) in magnetic thin films is crucial for optical data storage and spintronics.
• Previous studies attributed magnetoplasmonic enhancement of TMOKE to surface plasmon polariton (SPP) resonances.
• The role of grating geometry in modulating these effects was not fully understood.

Purpose of the Study:

• To investigate the influence of noble metal grating geometry on the TMOKE of a magnetic dielectric film.
• To explore the potential for enhancing, extinguishing, or switching the sign of TMOKE through resonance hybridization.
• To demonstrate a novel approach for controlling magnetoplasmonic effects without altering magnetization.

Main Methods:

• Fabrication of a hybrid structure: a magnetic dielectric film coated with a 1D noble metal grating.
• Characterization of the transverse magneto-optical Kerr effect.
• Analysis of the interplay between surface plasmon resonances and cavity resonances within the grating structure.

Main Results:

• The TMOKE enhancement is highly sensitive to the precise geometry of the noble metal grating.
• Hybridization of surface and cavity resonances leads to significant modulation of TMOKE: enhancement, extinction, and sign switching.
• These effects are achieved without changing the magnetic film's magnetization.

Conclusions:

• Grating geometry offers unprecedented control over magnetoplasmonic effects in magnetic dielectric films.
• The hybridization of surface and cavity resonances provides a powerful mechanism for tuning TMOKE.
• This research opens new avenues for applications in advanced sensing and nanophotonics.