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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

Electromagnetic wave with the frequency of 100 THz propagate through (a) the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40) and (b) the effective medium with the same effective parameters constructed with gold-air layered structure.The permittivity of gold is given by  and for bulk gold, the parameters are ωp = 2π × 2.175 × 1015s−1 and ωc = 2π × 6.5 × 1012s−1. The incidence angle is 30 degree and the filling factor of gold is 0.1.
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f2: Electromagnetic wave with the frequency of 100 THz propagate through (a) the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40) and (b) the effective medium with the same effective parameters constructed with gold-air layered structure.The permittivity of gold is given by and for bulk gold, the parameters are ωp = 2π × 2.175 × 1015s−1 and ωc = 2π × 6.5 × 1012s−1. The incidence angle is 30 degree and the filling factor of gold is 0.1.

Mentions: As an example, we simulate TM polarized electromagnetic waves with the frequency of 100 THz incident onto the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40, Fig. 2(a) and the effective medium constructed with gold-air layered structure (the filling factor of gold is 0.1, Fig. 2(b)), respectively. The simulated result is obtained with the use of the commercial software Comsol Multiphysics. The permittivity of gold is given by and for bulk gold, the plasma frequency ωp = 2π × 2.175 × 1015 s−1 and the collision frequency ωc = 2π × 6.5 × 1012 s−152. The incidence angle is 30 degree. Two media in Fig. 2(a) and 2(b) have the same constitutive parameters based on the effective medium theory. From the results, one can see the field distributions are identical in these two cases, indicating the layered metal-air structure can be well characterized as a homogeneous singular medium. Following the Drude model, /Re(εgold)/ will drop to a finite value from infinity as the frequency increases, especially when the frequency tends to the plasma frequency of gold. At this condition, the layered gold-air structure cannot exhibit the highly anisotropic property of finite ε⊥ and infinite ε//. This will introduce the loss of evanescent waves and therefore deteriorate the performance of hyperlens. However, this structure can still perform as a singular medium in a broad frequency band from microwave to Terahertz regimes as long as it meets the effective medium theory.


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)

Electromagnetic wave with the frequency of 100 THz propagate through (a) the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40) and (b) the effective medium with the same effective parameters constructed with gold-air layered structure.The permittivity of gold is given by  and for bulk gold, the parameters are ωp = 2π × 2.175 × 1015s−1 and ωc = 2π × 6.5 × 1012s−1. The incidence angle is 30 degree and the filling factor of gold is 0.1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Electromagnetic wave with the frequency of 100 THz propagate through (a) the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40) and (b) the effective medium with the same effective parameters constructed with gold-air layered structure.The permittivity of gold is given by and for bulk gold, the parameters are ωp = 2π × 2.175 × 1015s−1 and ωc = 2π × 6.5 × 1012s−1. The incidence angle is 30 degree and the filling factor of gold is 0.1.
Mentions: As an example, we simulate TM polarized electromagnetic waves with the frequency of 100 THz incident onto the homogeneous medium with high anisotropy (/Re(εy/εx)/ > 40, Fig. 2(a) and the effective medium constructed with gold-air layered structure (the filling factor of gold is 0.1, Fig. 2(b)), respectively. The simulated result is obtained with the use of the commercial software Comsol Multiphysics. The permittivity of gold is given by and for bulk gold, the plasma frequency ωp = 2π × 2.175 × 1015 s−1 and the collision frequency ωc = 2π × 6.5 × 1012 s−152. The incidence angle is 30 degree. Two media in Fig. 2(a) and 2(b) have the same constitutive parameters based on the effective medium theory. From the results, one can see the field distributions are identical in these two cases, indicating the layered metal-air structure can be well characterized as a homogeneous singular medium. Following the Drude model, /Re(εgold)/ will drop to a finite value from infinity as the frequency increases, especially when the frequency tends to the plasma frequency of gold. At this condition, the layered gold-air structure cannot exhibit the highly anisotropic property of finite ε⊥ and infinite ε//. This will introduce the loss of evanescent waves and therefore deteriorate the performance of hyperlens. However, this structure can still perform as a singular medium in a broad frequency band from microwave to Terahertz regimes as long as it meets the effective medium theory.

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