Experimental demonstration of negative refraction and subwavelength imaging by left-handed composite metamaterials

Ekmel Ozbay*, Koray Aydin, Gonca Ozkan, Irfan Bulu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

We report a true left-handed (LH) behavior and focusing in a composite metamaterial consisting of periodically arranged split ring resonator (SRR) and wire structures. The magnetic resonance of the SRR structure is demonstrated by comparing the transmission spectra of SRRs with that of closed SRRs. We confirmed experimentally that the effective plasma frequency of the LH material composed of SRRs and wires is lower than the plasma frequency of the wires. A well-defined left-handed transmission band with a peak value of -1.2 dB (-0.3 dB/cm) is obtained. We also report the transmission characteristics of a 2D composite metamaterial (CMM) structure in free space. At the frequencies where left-handed transmission takes place, we experimentally confirmed that the CMM structure has effective negative refractive index. Phase shift between consecutive numbers of layers of CMM is measured and phase velocity is shown to be negative at the relevant frequency range. Refractive index values obtained from the refraction experiments and the phase measurements are in good agreement and the experimental results agree extremely well with the theoretical calculations. By measuring the refracted electromagnetic (EM) waves from a LHM slab, we found an effective refractive index of -1.86. A 2D scanning transmission measurement technique was used to measure the intensity distribution of the electromagnetic (EM) waves that radiate from the point source. The flat lens behavior of a 2D CMM slab was demonstrated for two different point source distances of ds = 0.5λ and λ. The full width at half maximum of the focused beams is 0.36λ and 0.4λ, respectively, which are both below the diffraction limit.

Original languageEnglish (US)
Title of host publicationNegative Index Materials
Subtitle of host publicationFrom Microwave to Optical
PublisherMaterials Research Society
Pages43-54
Number of pages12
ISBN (Print)1558998764, 9781558998766
DOIs
StatePublished - 2006
Event2006 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 17 2006Apr 21 2006

Publication series

NameMaterials Research Society Symposium Proceedings
Volume919
ISSN (Print)0272-9172

Other

Other2006 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/17/064/21/06

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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