29 research outputs found
Composite metamaterials with dual-band magnetic resonances in the terahertz frequency regime
Composite metamaterials(CMMs) combining a subwavelength metallic hole array
(i.e. one-layer fishnet structure) and an array of split-ring resonators(SRRs)
on the same board are fabricated with gold films on silicon wafer. Transmission
measurements of the CMMs in the terahertz range have been performed. Dual-band
magnetic resonances, namely, a LC resonance at 4.40 THz and an additional
magnetic resonance at 8.64 THz originating from the antiparallel current in
wire pairs in the CMMs are observed when the electrical field polarization of
the incident light is parallel to the gap of the component SRR. The numerical
simulations agree well with the experimental results and further clarify the
nature of the dual-band magnetic resonances.Comment: 4 figures, 14 page
Surface plasmon polaritons assisted diffraction in periodic subwavelength holes of metal films with reduced interplane coupling
Metal films grown on Si wafer perforated with a periodic array of
subwavelength holes have been fabricated and anomalous enhanced transmission in
the mid-infrared regime has been observed. High order transmission peaks up to
Si(2,2) are clearly revealed due to the large dielectric constant contrast of
the dielectrics at the opposite interfaces. Si(1,1) peak splits at oblique
incidence both in TE and TM polarization, which confirms that anomalous
enhanced transmission is a surface plasmon polaritons (SPPs) assisted
diffraction phenomenon. Theoretical transmission spectra agree excellently with
the experimental results and confirm the role of SPPs diffraction by the
lattice.Comment: 4 pages, 5 figures, 26 reference
Influence of Intrinsic Electronic Properties on Light Transmission through Subwavelength Holes on Gold and MgB2 Thin Films
We show how intrinsic material properties modify light transmission through
subwavelength hole arrays on thin metallic films in the THz regime. We compare
the temperature-dependent transmittance of Au films and MgB films. The
experimental data is consistent with analytical calculations, and is attributed
to the temperature change of the conductivity of both films. The transmission
versus conductivity is interpreted within the open resonator model when taking
the skin depth into consideration. We also show that the efficiency of this
temperature control depends on the ratio of the transmission peak frequency to
the superconducting energy gap in MgB films.Comment: 6 pages, 6 figure