Search results for "Superlens"
showing 7 items of 7 documents
Interface engineering for improved light transmittance through photonic crystal flat lenses
2010
In this paper, we present photonic crystal flat lenses with interfaces engineered to improve the light transmittance thanks to a broad angles impedance matching. The interface engineering consists in the realization of antireflection gratings on the edges of the lenses which are designed to reduce the propagative waves reflectivity over a wide range of incident angles. The fabricated structures were measured in optical near-field and a four times enhancement of the light transmission efficiency is reported.
Diffraction-managed superlensing using plasmonic lattices
2012
Abstract We show that subwavelength diffracted wave fields may be managed inside multilayered plasmonic devices to achieve ultra-resolving lensing. For that purpose we first transform both homogeneous waves and a broad band of evanescent waves into propagating Bloch modes by means of a metal/dielectric (MD) superlattice. Beam spreading is subsequently compensated by means of negative refraction in a plasmon-induced anisotropic medium that is cemented behind. A precise design of the superlens doublet may lead to nearly aberration-free images with subwavelength resolution in spite of using optical paths longer than a wavelength.
Dyakonons in hyperbolic metamaterials
2013
We have analyzed surface-wave propagation that takes place at the boundary between an isotropic medium and a semi-infinite metal-dielectric periodic medium cut normally to the layers. In the range of frequencies where the periodic medium shows hyperbolic space dispersion, hybridization of surface waves (dyakonons) occurs. At low to moderate frequencies, dyakonons enable tighter confinement near the interface in comparison with pure SPPs. On the other hand, a distinct regime governs dispersion of dyakonons at higher frequencies. Full Text: PDF References Z. Ruan, M. Qiu, "Slow electromagnetic wave guided in subwavelength region along one-dimensional periodically structured metal surface", Ap…
Metamaterial coatings for subwavelength-resolution imaging
2011
Coating lenses are membranes made of materials exhibiting negative index of refraction and deposited on other media with high dielectric constant e 3 . Unfortunately far-field imaging suffers from centrosymmetric aberrations. We propose a simple procedure to compensate partially deviations from ray-tracing perfect imaging in asymmetric metamaterial lenses. We also show that, under some circumstances, coating superlens may recover subwavelength information transmitted in a relative spatial spectrum ranging from 1 to √e 3 .
Image formation with plasmonic nanostructures
2015
En 1873, Ernst Abbe concluyó que debido a la difracción de la luz el límite de resolución de un sistema óptico es aproximadamente la mitad de la longitud de onda de trabajo. Este límite, llamado el límite de difracción produce porque las ondas evanescentes no contribuyen a la formación de la imagen. En cualquier sistema óptico formado por materiales presentes en la naturaleza los detalles espaciales del objeto que sean más pequeños que el límite de resolución son transportados por ondas evanescentes. Normalmente estas ondas se pierden debido a la fuerte atenuación que experimentan viajando del objeto a la imagen. // En 1968, Veselago mostró que un material con permitividad y permeabilidad n…
Optical near-field microscopy of light focusing through a photonic crystal flat lens
2008
We report here the direct observation by using a scanning near-field microscopy technique of the light focusing through a photonic crystal flat lens designed and fabricated to operate at optical frequencies. The lens is fabricated using a III-V semiconductor slab, and we directly visualize the propagation of the electromagnetic waves by using a scanning near-field optical microscope. We directly evidence spatially, as well as spectrally, the focusing operating regime of the lens. At last, in light of the experimental scanning near-field optical microscope pictures, we discuss the lens ability to focus light at a subwavelength scale.
Diffraction-managed superlensing using metallodielectric heterostructures
2012
We show that subwavelength diffracted wave fields may be managed inside multilayered plasmonic devices to achieve ultra-resolving lensing. For that purpose we first transform both homogeneous waves and a broad band of evanescent waves into propagating Bloch modes by means of a metal/dielectric (MD) superlattice. Beam spreading is subsequently compensated by means of negative refraction in a plasmon-induced anisotropic effective-medium that is cemented behind. A precise design of the superlens doublet may lead to nearly aberration-free images with subwavelength resolution in spite of using optical paths longer than a wavelength. This research was funded by the Spanish Ministry of Economy and…