title: Asymmetric planar terahertz metamaterials.
abstract: We report an experimental observation of three distinct resonances in split ring resonators (SRRs) for both vertical and horizontal electric field polarizations at normal incidence by use of terahertz time-domain spectroscopy. Breaking the symmetry in SRRs by gradually displacing the capacitive gap from the centre towards the corner of the ring allows for an 85% modulation of the fundamental inductive-capacitive resonance. Increasing asymmetry leads to the evolution of an otherwise inaccessible high quality factor electric quadrupole resonance that can be exploited for bio-sensing applications in the terahertz region.
authors.affiliation: School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA. ranjan@lanl.gov
authors.forename: Ranjan
authors.initials: R
authors.lastname: Singh
authors.forename: Ibraheem A I
authors.initials: IA
authors.lastname: Al-Naib
authors.forename: Martin
authors.initials: M
authors.lastname: Koch
authors.forename: Weili
authors.initials: W
authors.lastname: Zhang