Au/Fe/Au multilayer transducers for magneto-optic surface plasmon resonance sensing

Abstract

In this paper, we analyze the magnetoplasmonic ͑MP͒ features and sensing capabilities of Au/Fe/Au trilayer structures, as transducers of the magneto-optic surface plasmon resonance ͑MOSPR͒ biosensor. This biosensor, which can surpass the sensitivity of the standard SPR sensor, is based on a MP modulation technique generated by the simultaneous stimulation of the surface plasmon polaritons ͑SPP͒ and the transversal magneto-optical Kerr effect ͑TMOKE͒. We study the magneto-optical activity of the trilayers as a function of the thickness and position of the Fe layer. We first demonstrate that this kind of structure allows modulating the SPP through an external magnetic field and moreover, induce a strong enhancement of the TMOKE effect. The modulation of the SPP is linearly proportional to the thickness of Fe layer and inversely proportional to the distance between the Fe layer and the external dielectric medium. Finally, we experimentally confirm a twofold increase in the MOSPR sensitivity with respect to the intensity-interrogated SPR biosensor in bulk refractive-index changes, keeping a similar chemical resistance and stability, unprecedented in other MP transducers, and biofunctionalization protocols.

Plasmonic nanodevice with magnetic funcionalities: fabrication and characterization

“…This type of structures exhibit localized surface plasmon resonance, while the ferromagnetic behavior can be tuned through the shape anisotropy. The second type of magneto-plasmonic systems consist in ferromagnetic/plasmonic multilayers, patterned or continious, being the most explored configuration a thin ferromagnetic layer embedded in a plasmonic film [8,12,[32][33][34][35][36]. This type of structures, present surface plasmon-polaritons propagating along the plasmonic metal surface.…”

Magnetic field modulation of chirooptical effects in magnetoplasmonic structures

“…[13] These two effects find application niches in, for example, sensing or telecommunications. [14,15,16,17,18,13] A magnetic field applied along the propagation direction of a circularly polarized light traveling in a chiral medium, does not modify the polarization state of the light and thus it induces no coupling between the eigenmodes of the chiral media. [19,20,21,22,23] Therefore, it is conceivable that plasmonic structures presenting simultaneously optical activity and magneto-optical properties are potential candidates to develop tuneable chiral structures whose properties could be controlled by a magnetic field.…”

Magneto-Optical Enhancement and Chemical Sensing Applications of Perpendicular Magnetic CoPt/Ag Stacked Structures with a ZnO Intermediate Layer

“…In general, the excitation of surface plasmon polaritons in these sensors requires total reection conditions using the Kretschmann-Raether con guration with an optical prism. [24][25][26][27] In contrast, an extraordinarily high θ K can be obtained in our MO cavity under simple measurement conditions using normal incident light. The MO cavity sensor monitors the modulation of light, and θ K of ±20 approximately corresponds to the intensity modulation of ±32% for the re ected light through a polarizer.…”

“…[20][21][22][23] Modulation techniques based on the combination of the MO effect and SPR have yielded chemical and biological sensors with high sensitivity. [24][25][26][27] In addition to a large MO effect, perpendicular magnetic anisotropy is a prerequisite for applications such as high-density magnetic and MO recording media, 28) high-resolution MO SLMs, 29,30) and spin electronic devices. [31][32][33] Large perpendicular magnetic anisotropy is required in spin electronics because random access memories need high-density memory cells.…”