Article

Super-resolution imaging through a planar silver layer

Optics Express (Impact Factor: 3.49). 04/2005; 13(6):2127-34. DOI: 10.1364/OPEX.13.002127
Source: PubMed

ABSTRACT

It has been proposed that a planar silver layer could be used to project a super-resolution image in the near field when illuminated near its plasma frequency [J. B. Pendry, Phys. Rev. Lett. 86, 3966 (2000)]. This has been investigated experimentally using a modified form of conformal-mask photolithography, where dielectric spacers and silver layers are coated onto a tungsten-on-glass mask. We report here on the experimental confirmation that super-resolution imaging can be achieved using a 50-nm thick planar silver layer as a near-field lens at wavelengths around 365 nm. Gratings with periods down to 145 nm have been resolved, which agrees well with our finite-difference time domain (FDTD) simulations.

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    • "Metamaterials are synthetic materials that are designed to exhibit surprising properties that are rarely found in nature. Following the first practical demonstration of negative refraction [1] and the perfect lens [2] [3] [4], there has been an explosion of interest in metamaterials. One of the most unusual classes of metamaterial structures is the class of hyperbolic metamaterials, which currently enjoys significant interest in optics and plasmonics [5], as well as acoustics and solid mechanics [6] [7] [8] [9] [10] [11] [12]. "
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    ABSTRACT: A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.
    Full-text · Article · Dec 2015
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    • "Consideration of just the first term in Eq. (4) would lead to the conclusion that a flat lens simply requires < 0. However, the higher order term in Eq. (4) has a sign opposite to that of the first term, indicating that increases in the thickness of a negative permittivity layer generally counteract phase conditions necessary to make a flat lens. Given the connection we have shown between a real paraxial image and a super-resolution image, this could explain why an early attempt to make a flat lens using a thicker silver layer did not achieve super-resolution [9] [10], whereas later attempts using thinner silver layers did [12] [13] [14]. "
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    ABSTRACT: We show that a classical imaging criterion based on angular dependence of small-angle phase can be applied to any system composed of planar, uniform media to determine if it is a flat lens capable of forming a real paraxial image and to estimate the image location. The real paraxial image location obtained by this method shows agreement with past demonstrations of far-field flat-lens imaging and can even predict the location of super-resolved images in the near-field. The generality of this criterion leads to several new predictions: flat lenses for transverse-electric polarization using dielectric layers, a broadband flat lens working across the ultraviolet-visible spectrum, and a flat lens configuration with an image plane located up to several wavelengths from the exit surface. These predictions are supported by full-wave simulations. Our work shows that small-angle phase can be used as a generic metric to categorize and design flat lenses.
    Full-text · Article · Dec 2014 · Optics Express
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    • "At present, the near-field superresolution optical imaging with silver layer superlens, photonic crystal, metal or medium metamaterial has been realized in the world. Among which, the use of SPPs (surface plasmon polaritons ) with metal nano structure to enhance the evanescent wave of the nanoscale structure information to realize optical superresolution imaging receives more attention from the researchers [8] [9] [10]. "
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    ABSTRACT: The optical transfer function of the far-field superlens imaging system is established in this thesis to make it easy to describe the corresponding relation between the far-field angular spectrum and the near-field object superresolution information. We utilized the established optical transfer function to make detailed research on the imaging characteristics of the far-field superresolution, also reconstruct the near-field nano-information through the far-field angular spectrum, which proves that the resolution of the far-field superlens with structure coupled with metal grating can reach 50 nm, and provides a helpful reference for the study of the new optical microscope imaging of superresolution. Crown Copyright
    Full-text · Article · Jan 2014 · Optik - International Journal for Light and Electron Optics
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