Resonant magneto–optical Kerr effect induced by hybrid plasma modes in ferromagnetic nanovoids

Abstract

With nanovoids buried in Co films, resonant structures were observed in spectra of polar magneto-optical Kerr effect (MOKE), where both a narrow bandwidth and high intensity were acquired. Through changing the thickness of Co films and the lattice of voids, different optical modes were introduced. For a very shallow array of voids, the resonant MOKE was induced by Ag plasma edge resonance, for deeper ones, hybrid plasma modes, such as void plasmons in the voids, surface lattice plasmons between the voids, and the co-action of them, etc. resulted in resonant MOKE. We found that resonant MOKE resulted from the void plasmons resonance which possesses the narrowest bandwidth for the lowest absorption of voids. The simulated electromagnetic field (EF) distribution consolidated different effects of these three optical modes on resonant MOKE modulation. Such resonant polar MOKE possesses high sensitivity, which might pave the way to on-chip MO devices.

Giant Goos–Hänchen shifts of waveguide coupled long-range surface plasmon resonance mode

“…This is due to the PWG structure and the LRSPR structure that are both of narrow resonance; normal mode splitting occurs when two narrow resonances are coupled together, resulting in the splitting of the SPR curve into two resonances. [14] According to Eq. ( 10), there is a direct relation between phase and GH shift, the sharper the phase jump, the larger the GH shift we can obtain, which indicates that we can obtain the larger shift around 34.736 • .…”

“…As described by Yin et al, [12] a lateral spatial displacement that is greater than 50 wavelengths for the reflected beam due to the surface plasmon polaritons (SPPs), was observed experimentally. The SPP is a perpendicularly confined evanescent electromagnetic wave that occurs at the metal-dielectric interface, [13][14][15] and it can be excited by attenuated total re-flection (ATR) configuration, where the wave vector mismatch between vacuum and SPP is compensated for by using highindex prisms. When SPPs are excited at the metal-dielectric interface, there will be a reflectance dip in the SPR reflectivity curve, and the electromagnetic fields near the interface will become very strong, which can lead to a giant GH shift.…”

Thickness dependent enhancement of the polar Kerr rotation in Co magnetoplasmonic nanostructures

“…This enhancement of the magnetooptical (M-O) effects, especially that of the polar and transversal Kerr effects, has been reported for both types of plasmonic excitations: localized surface plasmons (LSPs) [6][7][8][9][10][11][12] -and for propagating surface plasmon polaritons (SPPs) [13][14][15][16][17][18][19] . Examples include hybrid nanostructures of noble metal/ferromagnetic structures such as Co/Au 20 , YIG/Au 19 , and Au/Co/Au trilayers 16,[21][22][23] , as well as in patterned pure magnetic films [24][25][26][27][28][29][30][31][32] .…”

Enhancement and control of the Goos—Hänchen shift by nonlinear surface plasmon resonance in graphene

“…[18] On the other hand, exciting surface plasmons (SPs) is another effective method to enhance the shift. When SPs are excited at a metal-dielectric interface, the electromagnetic fields near the interface become very strong, [19][20][21][22][23] which can lead to a huge shift. The largest lateral shift observed in experiments is almost 50 times the wavelength of the incident beam.…”