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.
Highlights
Metamaterials - artificially structured composites - provide a design-based approach to create novel electromagnetic functionality
If the incident magnetic field is perpendicular to the plane of the split ring resonator (SRR), this will generate a magnetic dipole that is perpendicular to the SRR plane
While our MM/terbium gallium garnet (TGG) magneto-active devices have enabled direct imaging of the magnetic field with a resolution of λ /200, numerous other possibilities are worthy of detailed exploration
Summary
Metamaterials - artificially structured composites - provide a design-based approach to create novel electromagnetic functionality. SRRs are fabricated from high conductivity metals such as gold where incident electromagnetic radiation drives a circulating current The magnetic fields associated with these magnetic dipoles are of opposite sign, originate from a subwavelength area, and largely cancel in the far field. For both sSRRs and dSRRs, the near-field magnetic distribution is expected to be quite complex. Only simple microstrip lines have been investigated [8] while no direct measurements have been reported at THz frequencies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
