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Nikolay I. Zheludev

Publications and source records attributed to Nikolay I. Zheludev.

80 records · Page 5Linked to original sources
arXiv2010

Electromagnetic wave analogue of electronic diode

An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinary strong nonlinear wave propagation effect in the same way as electronic diode function is provided by a nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differing by a factor of 65.

physics.optics↗
arXiv2010

Highly tunable optical activity in planar achiral terahertz metamaterials

Using terahertz time domain spectroscopy we demonstrate tunable polarization rotation and circular dichroism in intrinsically nonchiral planar terahertz metamaterials without twofold rotational symmetry. The observed effect is due to extrinsic chirality arising from the mutual orientation of the metamaterial plane and the propagation direction of the incident terahertz wave.

physics.optics↗
arXiv2009

Giant nonlinearity of carbon nanotubes in a photonic metamaterial

Metamaterials, artificial media structured on the subwavelength scale offer a rich paradigm for developing unique photonic functionalities ranging from negative index of refraction and directionally asymmetric transmission to slowing light. Here we demonstrate that a combination of carbon nanotubes with a photonic metamaterial offers a new paradigm for the development of nonlinear media with exceptionally strong ultrafast nonlinear response invaluable in photonic applications. It is underpinned by strong coupling between weakly radiating Fano-type resonant plasmonic modes and the excitonic response of single-walled semiconductor carbon nanotubes. Using a "combinatorial" approach to material discovery we show that the optical response of such a composite system can be tailored and optimized by metamaterial design.

physics.optics↗
arXiv2008

Super-resolution without Evanescent Waves

The last decade has seen numerous efforts to achieve imaging resolution beyond that of the Abbe-Rayleigh diffraction limit. The main direction of research aiming to break this limit seeks to exploit the evanescent components containing fine detail of the electromagnetic field distribution at the immediate proximity of the object. Here we propose a solution that removes the need for evanescent fields. The object being imaged or stimulated with sub-wavelength accuracy does not need to be in the immediate proximity of the superlens or field concentrator: an optical mask can be designed that creates constructive interference of waves known as superoscillation, leading to a sub-wavelength focus of prescribed size and shape in a `field of view' beyond the evanescent fields, when illuminated by a monochromatic wave. Moreover, we demonstrate that such a mask may be used not only as a focusing device, but also as a super-resolution imaging device.

physics.optics↗
arXiv2008

Coherent and incoherent metamaterials and the order-disorder transitions

We demonstrate a new class of "coherent" metamaterials, where a regular ensemble of meta-molecules shows a collective, i.e. coherent, narrow band resonant response, while disordering the ensemble leads to broadening and eventually disappearance of the resonance. We draw parallels between the observed collective behavior of meta-molecules and the Mossbauer effect and notice certain remarkable similarities with the phase transitions of ferromagnetic systems.

physics.optics↗
arXiv2007

The plasmon Talbot effect

The plasmon analog of the self-imaging Talbot effect is described and theoretically analyzed. Rich plasmon carpets containing hot spots are shown to be produced by a row of periodically-spaced surface features. A row of holes drilled in a metal film and illuminated from the back side is discussed as a realizable implementation of this concept. Self-images of the row are produced, separated from the original one by distances up to several hundreds of wavelengths in the examples under consideration. The size of the image focal spots is close to half a wavelength and the spot positions can be controlled by changing the incidence direction of external illumination, suggesting the possibility of using this effect (and its extension to non-periodic surface features) for far-field patterning and for long-distance plasmon-based interconnects in plasmonic circuits, energy transfer, and related phenomena.

cond-mat.other↗
arXiv2004

Broken Time Reversal and Parity Symmetries for Electromagnetic Excitations in Planar Chiral Nanostructures

We elucidate the physical mechanisms by which electromagnetic excitations in planar chiral waveguides exhibit broken time reversal and parity symmetries as recently observed in metallic nanostructures (Phys. Rev. Lett. 91, 247404 (2003)). Furthermore, we show that concomitant with these broken symmetries the electromagnetic excitations can acquire fractional winding numbers, revealing analogies between light scattering from planar nanostructures and anyon matter.

cond-mat.mtrl-sci↗