Daoyong Li

Plasmon-enhanced magneto-optical activity in a nanostructure with circle annular arrays

The optical properties and magneto-optical (MO) activity in a bilayer nanostructure consisting of a ferromagnetic dielectric film and a noble metal film perforated with circle annular arrays are investigated. Enhanced Faraday rotation peaks with opposite signs are found. Meanwhile, enhanced polar Kerr rotation with large reflectance is also obtained at the same wavelength. The peak positions of the MO rotations accompanied by large transmittance and reflectance can be efficiently tailored by changing the geometrical parameters and the filling medium. These findings are important for applications in highly integrated optoelectronics and multiple channel magneto-optical devices.

Waveguide plasmon resonance induced enhancement of the magneto-optics in a Ag/Bi:YIG bilayer structure

The optical transmission and magneto-optical (MO) activity in the bilayer systems of a silver film perforated with nanohole arrays and a uniform dielectric film magnetized perpendicular to its plane are investigated. A new peak corresponding to magneto-optic enhancement in the visible region is found, which mainly originates from the interplay of surface plasmon polaritons, localized surface plasmon resonance, and the waveguide resonance. The peak positions of the MO rotations accompanied with large transmittance can be efficiently tailored by changing the geometrical parameters and the filling medium. These findings have significant impacts and applications in highly integrated optoelectronic and MO devices.

Enhancement of magneto-optical Faraday effects and extraordinary optical transmission in a tri-layer structure with rectangular annular arrays.

The properties of optics and magneto-optical Faraday effects in a metal-dielectric tri-layer structure with subwavelength rectangular annular arrays are investigated. It is noteworthy that we obtained the strongly enhanced Faraday rotation of the desired sign along with high transmittance by optimizing the parameters of the nanostructure in the visible spectral ranges. In this system, we obtained two extraordinary optical transmission (EOT) resonant peaks with enhanced Faraday rotations, whose signs are opposite, which may provide the possibility of designing multi-channel magneto-optical devices. Study results show that the maximum of the figure of merit (FOM) of the structure can be obtained between two EOT resonant peaks accompanied by an enhanced Faraday rotation. The positions of the maximum value of the FOM and resonant peaks of transmission along with a large Faraday rotation can be tailored by simply adjusting the geometric parameters of our models. These research findings are of great importance for future applications of magneto-optical devices.

Fano resonance and magneto-optical Kerr rotaion in periodic Co/Ni complex plasmonic nanostructure

We report a pure ferromagnetic metallic magnetoplasmonic structure consisting of two-dimensional ordered Ni nanodisks array on Co film. With a sufficient height of the nanodisks, a steep and asymmetric Fano resonance can be excited in this structure. We attribute the fascinating spectral lineshape to the strong coupling between the excitation of surface plasmon polaritons at the interface and the localized surface plasmon resonance of nanodisks. The conclusion is fully confirmed by spectrum measurements in nanostructures with different heights. Furthermore, the enhancement and sign of the magneto-optical Kerr rotation in this structure are significantly modified by the Fano resonance.

Magneto-optical properties of one-dimensional orderly nanocorrugation made from magnetic quadrilayer films

Magneto-optical (MO) Kerr effect and optical reflectance are investigated in the visible light region for one-dimensional orderly nanocorrugation of magnetic quadrilayer films. We find that the MO enhancement originates from the combined action between cavity effect and surface plasmon resonance. The coupling between surface plasmon polaritions and localized surface plasmons cannot only enhance the magnitude of Kerr angle, but also alter the sign of Kerr rotation. In addition, the MO properties on the nanocomposite films can be tuned by the thickness of the intermediate HfO2 layer due to the cavity effect in multilayer.

Plasmonics Resonance Enhance Magneto-Optical Effects Through Metallic Sub-wavelength Grating with Bismuth Iron Garnet Slab

We theoretically investigated an enhancement of the magneto-optical Faraday rotations along with large transmittance in two multilayer structures. The shifts of the Faraday rotation peaks are more obvious than the transmittance peaks when the grating period is changed, which is beneficial to acquire the large Faraday rotation and transmittance. The Faraday rotation of tri-layer system is five times larger than the bilayer system, and the Faraday resonance peak can be mediated by changing the refractive index or thickness of the additional nonmagnetic dielectric layer (NDL) layer. These results are important for applications in highly integrated optoelectronic and magneto-optical devices.