Limits...
Realization of deep subwavelength resolution with singular media.

Xu S, Jiang Y, Xu H, Wang J, Lin S, Chen H, Zhang B - Sci Rep (2014)

Bottom Line: The record of imaging resolution has kept being refreshed in the past decades and the best resolution of hyperlenses and superlenses so far is about one out of tens in terms of wavelength.The meta-lens is made of subwavelength metal/air layers, which exhibit singular medium property over a broad band.As a proof of concept, the subwavelength imaging ability is demonstrated over a broad frequency band from 1.5-10 GHz with the resolution varying from 1/117 to 1/17 wavelength experimentally.

View Article: PubMed Central - PubMed

Affiliation: 1] The Electromagnetics Academy at Zhejiang University, Zhejiang University, Hangzhou 310027, China [2] State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China [3] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [4] Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore.

ABSTRACT
The record of imaging resolution has kept being refreshed in the past decades and the best resolution of hyperlenses and superlenses so far is about one out of tens in terms of wavelength. In this paper, by adopting a hybrid concept of transformation optics and singular media, we report a broadband meta-lens design methodology with ultra-high resolution. The meta-lens is made of subwavelength metal/air layers, which exhibit singular medium property over a broad band. As a proof of concept, the subwavelength imaging ability is demonstrated over a broad frequency band from 1.5-10 GHz with the resolution varying from 1/117 to 1/17 wavelength experimentally.

No MeSH data available.


Related in: MedlinePlus

(a) A two-dimensional scheme of an unconventional lens for TM waves. (b) The k surfaces for an isotropic medium (circle in blue) and a singular medium (parallel lines in red). (c) The corresponding virtual space of materials in (b). In isotropic materials, energy flow  will spread out in all the directions. After squeezing the original virtual space (the regime in blue) in the azimuthal direction,  can only propagate in the transformed tube-like space (the regime in red) without spreading out. (d) The metamaterial with infinite anisotropy is made of metal-air structure with the period pϕ and the thickness of metal dm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4048882&req=5

f1: (a) A two-dimensional scheme of an unconventional lens for TM waves. (b) The k surfaces for an isotropic medium (circle in blue) and a singular medium (parallel lines in red). (c) The corresponding virtual space of materials in (b). In isotropic materials, energy flow will spread out in all the directions. After squeezing the original virtual space (the regime in blue) in the azimuthal direction, can only propagate in the transformed tube-like space (the regime in red) without spreading out. (d) The metamaterial with infinite anisotropy is made of metal-air structure with the period pϕ and the thickness of metal dm.

Mentions: The scheme of a TM cylindrical meta-lens is shown in Fig. 1(a). Two point sources are located closely at the inner boundary of the lens with subwavelength distance. For a specific material, the dispersion relation of electromagnetic waves can be written as in cylindrical coordinates, where kρ and kϕ are wave vectors along the ρ and ϕ directions, εϕ and ερ are the permittivities along the ϕ and ρ directions, μz is the permeability along z direction, and ω is the angular frequency of incident waves. The k surface for free space exhibits a circular shape (blue curve in Fig. 1(b)) and the energy flow of electromagnetic waves will spread out during propagation because of diffraction and loss of evanescent waves with tangential wave vector kϕ > k0. The medium with hyperbolic dispersion, which is adopted in hyperlens design, keeps the large tangential wave vector coefficient kϕ propagating without being evanescent.


Realization of deep subwavelength resolution with singular media.

Xu S, Jiang Y, Xu H, Wang J, Lin S, Chen H, Zhang B - Sci Rep (2014)

(a) A two-dimensional scheme of an unconventional lens for TM waves. (b) The k surfaces for an isotropic medium (circle in blue) and a singular medium (parallel lines in red). (c) The corresponding virtual space of materials in (b). In isotropic materials, energy flow  will spread out in all the directions. After squeezing the original virtual space (the regime in blue) in the azimuthal direction,  can only propagate in the transformed tube-like space (the regime in red) without spreading out. (d) The metamaterial with infinite anisotropy is made of metal-air structure with the period pϕ and the thickness of metal dm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048882&req=5

f1: (a) A two-dimensional scheme of an unconventional lens for TM waves. (b) The k surfaces for an isotropic medium (circle in blue) and a singular medium (parallel lines in red). (c) The corresponding virtual space of materials in (b). In isotropic materials, energy flow will spread out in all the directions. After squeezing the original virtual space (the regime in blue) in the azimuthal direction, can only propagate in the transformed tube-like space (the regime in red) without spreading out. (d) The metamaterial with infinite anisotropy is made of metal-air structure with the period pϕ and the thickness of metal dm.
Mentions: The scheme of a TM cylindrical meta-lens is shown in Fig. 1(a). Two point sources are located closely at the inner boundary of the lens with subwavelength distance. For a specific material, the dispersion relation of electromagnetic waves can be written as in cylindrical coordinates, where kρ and kϕ are wave vectors along the ρ and ϕ directions, εϕ and ερ are the permittivities along the ϕ and ρ directions, μz is the permeability along z direction, and ω is the angular frequency of incident waves. The k surface for free space exhibits a circular shape (blue curve in Fig. 1(b)) and the energy flow of electromagnetic waves will spread out during propagation because of diffraction and loss of evanescent waves with tangential wave vector kϕ > k0. The medium with hyperbolic dispersion, which is adopted in hyperlens design, keeps the large tangential wave vector coefficient kϕ propagating without being evanescent.

Bottom Line: The record of imaging resolution has kept being refreshed in the past decades and the best resolution of hyperlenses and superlenses so far is about one out of tens in terms of wavelength.The meta-lens is made of subwavelength metal/air layers, which exhibit singular medium property over a broad band.As a proof of concept, the subwavelength imaging ability is demonstrated over a broad frequency band from 1.5-10 GHz with the resolution varying from 1/117 to 1/17 wavelength experimentally.

View Article: PubMed Central - PubMed

Affiliation: 1] The Electromagnetics Academy at Zhejiang University, Zhejiang University, Hangzhou 310027, China [2] State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China [3] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [4] Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore.

ABSTRACT
The record of imaging resolution has kept being refreshed in the past decades and the best resolution of hyperlenses and superlenses so far is about one out of tens in terms of wavelength. In this paper, by adopting a hybrid concept of transformation optics and singular media, we report a broadband meta-lens design methodology with ultra-high resolution. The meta-lens is made of subwavelength metal/air layers, which exhibit singular medium property over a broad band. As a proof of concept, the subwavelength imaging ability is demonstrated over a broad frequency band from 1.5-10 GHz with the resolution varying from 1/117 to 1/17 wavelength experimentally.

No MeSH data available.


Related in: MedlinePlus