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

Abstract

Optical and magneto-optical properties of periodic Co double layer film * Xia Wen-Bin(夏文斌) a) , Gao Jin-Long(高锦龙) a) , Zhang Shao-Yin(张绍银) b) , Chen Le-Yi(陈乐易) a) , Tang Yan-Mei(唐妍梅) a) , Tang Shao-Long(唐少龙) a) † , and Du You-Wei(都有为) a) a)

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

“…Besides the LSP resonance from the single Ni nanodisk, the ordered array can excite SPP modes at the interface by grating coupling. The momentum match condition can be used to obtain the relation between the wavelength of the incident light and the incident angle for the given diffraction orders and the certain period, which can be expressed as [26] k spp (λ ) = 2π…”

“…The longitudinal MO Kerr rotation was measured at ϕ = 0 • and θ = 45 • for TM-polarized light with a home-made MOKE measurement system. [26] The magnetic field up to 1.5 kOe was applied in longitudinal configuration using an electromagnet. The weighted summation of the measured results of Co and Ni flat films according to the area fraction in our samples was shown as a reference.…”

“…In our previous work on Co antidots film and Co double layer film, the interaction between different orders' SPPs leads to variety of line shapes of the Kerr spectrum and the enhancement of the MO signal. [26,27] Especially, in Co double layer film, it has been proposed as a possible explanation that an unusual sign change of the Kerr angles is due to the interaction between SPPs from bottom layer and LSPs from top layer. [26] In Sample B, the sign change is observed again.…”

“…[26,27] Especially, in Co double layer film, it has been proposed as a possible explanation that an unusual sign change of the Kerr angles is due to the interaction between SPPs from bottom layer and LSPs from top layer. [26] In Sample B, the sign change is observed again. By the comparison between Sample A and B, it is clear that it is the Fano resonance which results in the sign change and the existence of the LSP mode, and Fano resonance is closely linked with the heights of the Ni disks.…”