Surface Plasmon and Fabry-Perot Enhanced Magneto-Optical Kerr Effect in Graphene Microribbons

A single sheet of graphene exhibits the ability to turn polarization of light by several degrees in modest magnetic fields. Here we demonstrate that giant angle rotation in graphene in the terahertz range can be realized and further increased by the introduction of surface plasmon and constructive Fabry Perot interference with the supporting substrate. The maximum Kerr rotation angle is up to 15° in a single layer of graphene ribbons at 6 TPIz for the applied magnetic field 4 T. Such a magnification in magneto-optical Kerr effect can be realized in a fairly large incident angle.

Surface plasmon polaritons generated magneto–optical Kerr reversal in nanograting

Controlling the phase of light in magnetoplasmonic structures is receiving increasing attention because of its already shown capability in ultrasensitive and label-free molecular-level detection.Magneto-optical Kerr reversal has been achieved and well explained in nanodisks by using the phase of localized plasmons.In this paper,we report that the Kerr reversal can also be produced by surface plasmon polaritons independently.We experimentally confirm this in Co and Ag/Co/Ag metal nanogratings,and can give a qualitative explanation that it is the charge accumulation at the interface between the grating surface and air that acts as the electromagnetic restoring force to contribute necessary additional phase for Kerr reversal.Our finding can enrich the means of designing and fabricating magneto-optical-based biochemical sensors.

High sensitivity side-hole fiber magnetic field sensor,based on surface plasmon resonance

A high sensitivity magnetic fluid（MF） filled side-hole fiber magnetic field sensor based on surface plasmon resonance（SPR） is designed and investigated.Within the side-hole fiber,the water-based MF is injected into the two side holes,and both of the holes are coated with gold to realize the measurement of the magnetic field by using the SPR effect.The refractive index of the MF changes with different external magnetic fields,resulting in the resonant wavelength moving to other wavelengths.Furthermore,when the external magnetic field increases from 30 to 210.9 Oe,the magnetic field sensitivity can reach to 1.063 nm/Oe.

Optical and magneto–optical properties of periodic Co double layer film

Co double layer film （CoDLF） consisting of a disk-array layer and an antidot-array layer, both with square order, was investigated. Both the reflectivity and Kerr spectra of CoDLF show anisotropic effects when the azimuthal angle of incident light changes. From the simulation result of surface plasmon polaritons （SPPs）, we attribute the reflectivity minima and Kerr angle maxima in the spectra mainly to the excitation of different diffractional orders＇ SPPs. More interestingly, the Kerr angle changes sign at specific wavelengths. We attribute these phenomena to the excitation of SPPs and localized surface plasmons （LSPs）, and the interaction between them.

Synthesis of yttrium iron garnet/bismuth quantum dot heterostructures with localized plasmon enhanced magneto-optical performance

Interactions between light and magnetic matter attracted great attention lately due to their potential applications in nanophotonics,spintronics,and high-accuracy sensing.Here,we grew bismuth quantum dots(Bi–QDs)with strong spin–orbit coupling on a magnetic insulator yttrium iron garnet(YIG)via molecular beam epitaxy.The YIG/Bi–QDs material shows an enhanced magneto-optical Kerr rotation up to 130%compared with that of a bare YIG film.The Bi–QDs were also introduced onto a lutetium–bismuth co-doped YIG film to form a hybrid system with remarkably enhanced Kerr rotation(from 1626 to 2341 mdeg).Ferromagnetic resonance measurements showed an increased effective magnetization as well as interfacial spin–orbit field in the YIG/Bi–QD heterostructures.Localized plasmons were mapped using electron energy loss spectroscopy with high spatial resolution,revealing enhanced plasmon intensity at both the Bi–QD surface and YIG/Bi–QD interface.Introducing Bi-QDs onto the YIG film enhanced Kerr rotation owing to the attenuated optical reflection and increased effective magnetization.The Bi–QDenhanced magneto-optical effect enables development of efficient nanoscale light switching,spintronics,and even plasmonic nano-antennas.