We demonstrate a giant enhancement of the transverse magneto-optical Kerr effect. In contrast to conventional magnetoplasmonic structures, we exploit surface plasmon resonances (SPRs) excited along the surface of a ferromagnetic substrate on which a uniaxial $\varepsilon$-near-zero (ENZ) metamaterial is grown. In this design, bulky prism couplers are not required and SPR sensors can be produced in integrated, miniaturized systems. We also obtained the analytical expression for the ENZ-SPR phase-matching condition, which can be used for the straightforward design of plasmonic and magnetoplasmonic devices.

• Received 30 July 2020
• Revised 21 September 2020
• Accepted 22 September 2020

DOI:https://doi.org/10.1103/PhysRevB.102.165304