We propose a highly sensitive sensor based on enhancing the transversal magneto-optical Kerr effect (TMOKE) through excitation of surface plasmon resonances in a novel and simple architecture, which consists of a metal grating on a metal magneto-optical layer. Detection of the change in the refractive index of the analyte medium is made by monitoring the angular shift of the Fano-like resonances associated with TMOKE. A higher resolution is obtained with this technique than with reflectance curves. The key aspect of the novel architecture is to achieve excitation of surface plasmon resonances mainly localized at the sensing layer, where interaction with the analyte occurs. This led to a high sensitivity, S = 190° RIU–1, and high performance with a figure of merit of the order of 103, which can be exploited in sensors and biosensors.

We demonstrate numerically a concept for highly integrated magnetoplasmonic biosensors made with nanostructured magnetooptical (MO) hyperbolic metamaterials (HMMs). The concept is based on the use of enhanced amplitudes of ultranarrow peaks of the transverse magnetooptical Kerr effect (TMOKE). In contrast to conventional magnetoplasmonic transducers that employ wide surface plasmon resonances, we use bulk plasmon polariton modes in HMMs. In sensing through changes in the refractive index of water, a figure of merit on the order of 8 × 102 was observed, to be compared with 590 for non-MO HMMs. This allows for improved resolution detection of low-molecular-weight analytes at concentrations on the order of picomolar.

We demonstrate a concept for the giant enhancement of the transverse magneto-optical Kerr effect (TMOKE) using bulk plasmon polariton (BPP) modes in non-magnetic multilayer hyperbolic metamaterials (HMMs). Since the BPP modes are excited through the attenuated total reflection (ATR) mechanism, using a Si-based prism-coupler, we considered a single dielectric magneto-optical (MO) spacer between the prism and the HMM. The working wavelength was estimated, using the effective medium approach for a semi-infinite dielectric-plasmonic multilayer, considering the region where the system exhibits type II HMM dispersion relations. Analytical results, by means of the scattering matrix method (SMM), were used to explain the physical principle behind our concept. Numerical results for giant TMOKE values (close to their maximum theoretical values, ±1) were obtained using the finite element method (FEM), applying the commercial software COMSOL Multiphysics. Our proposal comprises a simple and experimentally feasible structure that enables the study of MO phenomena in HMMs, which may find application in future nanostructured magnetoplasmonic metamaterials for active nanophotonic devices.

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In this work, we theoretically demonstrate the giant increment of the transversal magneto-optical Kerr effect in a type II hyperbolic metamaterial composed of four pairs of dielectric/metal layers, where the dielectric material presents magneto-optical activity. The enhancement is a consequence of high localization of the electromagnetic field inside the metamaterial given by excitation of the lowest order—bulk plasmon polariton mode.