Browsing by Subject "Refraction index"

Now showing 1 - 3 of 3

Open Access
Negative refraction and superlens behavior in a two-dimensional photonic crystal
(American Physical Society, 2005) Moussa, R.; Foteinopoulou, S.; Zhang, L.; Tuttle, G.; Guven, K.; Özbay, Ekmel; Soukoulis, C. M.
We experimentally and theoretically studied a left-handed structure based on a photonic crystal (PC) with a negative refractive index. The structure consists of triangular array of rectangular dielectric bars with dielectric constant 9.61. Experimental and theoretical results demonstrate the negative refraction and the superlensing phenomena in the microwave regime. The results show high transmission for our structure for a wide range of incident angles. Furthermore, surface termination within a specific cut of the structure excite surface waves at the interface between air and PC and allow the reconstruction of evanescent waves for a better focus and better transmission. The normalized average field intensity calculated in both the source and image planes shows almost the same full width at half maximum for the source and the focused beam.
Open Access
Negative refraction by photonic crystals
(Nature, 2003) Cubukcu, E.; Aydin, K.; Özbay, Ekmel; Foteinopoulou, S.; Soukoulis, C. M.
Open Access
Spectral negative refraction and focusing analysis of a two-dimensional left-handed photonic crystal lens
(American Physical Society, 2004-11) Güven, Kaan; Aydın, Koray; Alıcı, Kamil Boratay; Soukoulis, C. M.; Özbay, Ekmel
We report the spectral refraction analysis and focusing properties of a two-dimensional, dielectric photonic crystal (PC) slab in freespace. A transverse electric polarized upper band of the crystal is used. The measured refraction spectra indicates that a highly isotropic negative index of refraction is present in the measured frequency range of the band. We demonstrate experimentally and numerically the focusing of the field emitted from an omnidirectional source placed in front of the crystal. Both the source and the focus pattern are away from the PC interfaces of the order of several wavelengths. The focus pattern mimics the arbitrary lateral and longitudinal shifts of the source, which is a manifestation of true flat lens behavior.