title: THz near-field Faraday imaging in hybrid metamaterials.
abstract: We report on direct measurements of the magnetic near-field of metamaterial split ring resonators at terahertz frequencies using a magnetic field sensitive material. Specifically, planar split ring resonators are fabricated on a single magneto-optically active terbium gallium garnet crystal. Normally incident terahertz radiation couples to the resonator inducing a magnetic dipole oscillating perpendicular to the crystal surface. Faraday rotation of the polarisation of a near-infrared probe beam directly measures the magnetic near-field with 100 femtosecond temporal resolution and (λ/200) spatial resolution. Numerical simulations suggest that the magnetic field can be enhanced in the plane of the resonator by as much as a factor of 200 compared to the incident field strength. Our results provide a route towards hybrid devices for dynamic magneto-active control of light such as isolators, and highlight the utility of split ring resonators as compact probes of magnetic phenomena in condensed matter.
authors.affiliation: Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands.
authors.forename: Nishant
authors.initials: N
authors.lastname: Kumar
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Strikwerda
authors.forename: Kebin
authors.initials: K
authors.lastname: Fan
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Richard D
authors.initials: RD
authors.lastname: Averitt
authors.forename: Paul C M
authors.initials: PC
authors.lastname: Planken
authors.forename: Aurèle J L
authors.initials: AJ
authors.lastname: Adam
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D005708:Gallium / Q000737:chemistry; D008027:Light; D060526:Magnetic Fields; D008280:Magnetics; D010825:Physics / Q000379:methods; D012031:Refractometry / Q000379:methods; D012542:Scattering, Radiation; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D055053:Terahertz Radiation; D013725:Terbium / Q000737:chemistry; D013997:Time Factors
chemical_list: D013725:Terbium; D005708:Gallium