Abstracts - Dipartimento di Elettronica Applicata

Meta 2010 & FEM 2010 – Rome, 13-15 December 2010
Cut-Wire-Induced Enhanced Transmission through
Sub-Wavelength Slits
Emiliano Di Gennaro (1) , Ilaria Gallina (2) , Antonello Andreone (1) ,
Giuseppe Castaldi (2) , and Vincenzo Galdi (1)
(1) CNR-SPIN and University of Naples “Federico II,” Department of Physics
Naples, Italy – E-mail: emiliano@na.infn.it, andreone@unina.it
(2) University of Sannio, Department of Engineering
Benevento, Italy – E-mail: ilaria.gallina@unisannio.it, castaldi@unisannio.it,
vgaldi@unisannio.it
The study of extraordinary transmission phenomena through sub-wavelength
apertures (holes, slits, grooves, etc.) has recently elicited a great attention from both
theoretical and application viewpoints (see, e.g., [1] for a recent review).
It has recently been shown [1] that substantial (nearly 800-fold) transmission
enhancements of transverse-electric (TE) fields through sub-wavelength slits in a thin
metallic screen can be obtained by placing a metallic cut-wire array (with the wires
centered on the slits and parallel to them) on a thin dielectric substrate at the side of
the screen that is directly illuminated. Such phenomenon was shown to be attributable
to the excitation of an electric (dipole-like) resonance in the cut wires, whose strong
field localization near the input aperture of the slit allows effective coupling of the
illuminating plane-wave with the evanescent spectrum, and thus its “squeezing”
through the slits.
Here, we report on some recent results which extend the above studies to the case of
paired cut-wire arrays [2], and provide an experimental verification [3] of the
phenomena. Experimental results, on printed-circuit-board prototypes operating at
microwave frequencies, agree fairly well with numerical full-wave simulations [4].
Besides the moderately higher transmission enhancement, by comparison with [1], the
proposed scenario features a richer phenomenology, which involves both electric- and
magnetic-type resonances, typical of cut-wire-pair structures, thereby endowing
further degrees of freedom in the engineering of enhanced transmission (e.g., passband-type
designs).
References
[1] F. J. García-Vidal, L. Martín-Moreno, T. W. Ebbesen, and L. Kuipers, “Light passing through
subwavelength apertures,” Rev. Mod. Phys., 82, 729-787, 2010
[2] Y. Q. Ye and Y. Jin, “Enhanced transmission of transverse electric waves through subwavelength
slits in a thin metallic film” Phys. Rev. E, 80, 036606, 2009
[3] I. Gallina, G. Castaldi, V. Galdi, E. Di Gennaro, and A. Andreone, “Paired cut-wire arrays for
enhanced transmission of transverse-electric fields through subwavelength slits in a thin metallic
screen,” IEEE Antennas Wireless Propagat. Lett., 9, 641-644, 2010
[4] E. Di Gennaro, I. Gallina, A. Andreone, G. Castaldi, and V. Galdi, “Experimental evidence of cutwire-induced
enhanced transmission of transverse-electric fields through sub-wavelength slits in a
thin metallic screen,” to be published in Opt. Express, 2010
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