Browsing by Subject "Enhanced transmission"

Now showing 1 - 6 of 6

Open Access
Enhanced transmission through a sub-wavelength aperture: resonant approaches employing metamaterials
(Institute of Physics Publishing Ltd., 2009-09-17) Bilotti, F.; Scorrano, L.; Özbay, Ekmel; Vegni, L.
In this paper, we propose a number of resonant metamaterial-based approaches to enhance the power transmission through sub-wavelength apertures. The extraordinary transmission beyond the diffraction limit is usually obtained using setups that rely on covers supporting proper surface plasmon polaritons or leaky waves. However, the actual implementation in real-life applications of these structures is strongly limited by their large transverse extension. After briefly reviewing the aforementioned limitations, we present in the paper new setups based on resonant approaches, characterized by covers whose transverse dimensions are of the same order of magnitude as the aperture size. The phenomenology of the enhanced transmission, the related theoretical aspects, the results of the numerical simulations and the successful experimental verification using the newly proposed setups are then presented in detail.
Open Access
Extracting power from sub-wavelength apertures by using electrically small resonators: Phenomenology, modeling, and applications
(IEEE, 2012) Bilotti F.; Di Palma L.; Ramaccia, D.; Toscano, A.; Vegni L.; Ateş, Damla; Özbay, Ekmel
In this contribution, we review our recent work on the extraction of the electromagnetic power from electrically small apertures by using metamaterial-inspired resonators. First, we present an antenna interpretation of the power transmission through sub-wavelength apertures and discuss the questioned concept of 'enhanced transmission'. Then, we present the so-called 'connected bi-omega particle' and the related analytical model. After that, exploiting proper numerical and experimental examples, we also show that the electromagnetic response of such a particle is not influenced by the surrounding environment. This unique property makes the particle a suitable candidate for the implementation of microwave components based on the selective power extraction from electrically small apertures. Finally, the application of the proposed concepts to the design of innovative microwave components, such as waveguide filters, diplexers, power-splitters, modal filters, horn antennas, etc. will be considered and demonstrated through proper numerical and experimental results. © 2012 IEEE.
Open Access
Grating coupler integrated photodiodes for plasmon resonance based sensing in fluidic systems
(IEEE, 2011) Türker, Burak; Güner, Hasan; Ayaş, Sencer; Ekiz, Okan O.; Acar, Handan; Güler, Mustafa O.; Dâna, Aykutlu
We demonstrate an integrated sensor combining a grating-coupled plasmon resonance surface with a planar photodiode. Plasmon enhanced transmission is employed as a sensitive refractive index (RI) sensing mechanism and monitored via the integrated photodiode. © 2011 OSA.
Open Access
The magical world of metamaterials
(SPIE, 2009) Çağlayan, Hümeyra; Özbay, Ekmel
We review experimental and theoretical studies performed on left-handed metamaterials (LHM). The metamaterials exhibit quiet unusual electromagnetic properties such as negative refraction, negative phase velocity, subwavelength focusing, subwavelength cavities and enhanced transmission.
Open Access
Plasmonic structures with extraordinary transmission and highly directional beaming properties
(Wiley Periodicals, 2006) Cağlayan, H.; Bulu, I.; Özbay, Ekmel
We studied the grating-coupling phenomena between surface plasmons and electromagnetic waves in the microwave spectrum. We first present the experimental and theoretical results of an enhanced microwave transmission though a subwavelength circular annular aperture with and without metallic gratings. We demonstrate that a 145-fold enhancement factor could be obtained with a subwavelength circular annular aperture that was surrounded by periodic metallic gratings. This was assisted by the guided mode of the coaxial waveguide and by coupling to the surface plasmons. We present the angular transmission distributions from circular annular apertures, and circular annular apertures surrounded by concentric periodic grooves. At the surface mode resonance frequency, the transmitted electromagnetic waves from the subwavelength circular annular aperture surrounded by concentric periodic grooves have a strong angular confinement with an angular divergence of ±3°. We demonstrate that only the output surface is responsible for the beaming effect. Furthermore, we present the field distributions and showed that there is no beaming effect at the off-resonance frequency. © 2006 Wiley Periodicals, Inc.
Open Access
Resonant excitation of surface plasmons in one-dimensional metallic grating structures at microwave frequencies
(Institute of Physics Publishing, 2005) Akarca-Biyikli, S. S.; Bulu, I.; Özbay, Ekmel
Grating-coupling phenomena between surface plasmons and electromagnetic waves were studied in the microwave spectrum using metallic gratings. Transmission measurements were carried out to observe the transmitted radiation around the surface plasmon resonance frequencies. Grating structures with subwavelength apertures were designed for transmission experiments. Measurements were made in the microwave spectrum of 10-37.5 GHz, corresponding to a wavelength region of 8-30 mm. The A1 samples had a grating periodicity of 16 mm. A 2 mm wide subwavelength slit was opened for transmission samples. Samples with one/double-sided gratings displayed remarkably enhanced transmission and directivity with respect to the reference sample without gratings. The experimental results agreed well with theoretical simulations. ∼50% transmission at 20.7 mm, ∼25-fold enhancement, and ±4° angular divergence were achieved with a ∼λ/10 aperture.